diff --git a/internal/handlers/active_area.go b/internal/handlers/active_area.go
index 671db1c7..332151b1 100644
--- a/internal/handlers/active_area.go
+++ b/internal/handlers/active_area.go
@@ -12,6 +12,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/active_areas"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/repositories"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/utils"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
@@ -42,17 +43,17 @@ func (area ActiveArea) GetActiveAreasFunc(repository domain.ActiveAreaRepository
 		orderColumn := utils.GetValueByPointerOrDefaultValue(a.OrderColumn, order.FieldID)
 		total, err := repository.TotalActiveAreas(ctx)
 		if err != nil {
-			area.logger.Error("failed to query total active areas", zap.Error(err))
+			area.logger.Error(messages.ErrQueryTotalAreas, zap.Error(err))
 			return active_areas.NewGetAllActiveAreasDefault(http.StatusInternalServerError).
-				WithPayload(buildErrorPayload(err))
+				WithPayload(buildInternalErrorPayload(messages.ErrQueryTotalAreas, err.Error()))
 		}
 		var e []*ent.ActiveArea
 		if total > 0 {
 			e, err = repository.AllActiveAreas(ctx, int(limit), int(offset), orderBy, orderColumn)
 			if err != nil {
-				area.logger.Error("failed to query active areas", zap.Error(err))
+				area.logger.Error(messages.ErrQueryAreas, zap.Error(err))
 				return active_areas.NewGetAllActiveAreasDefault(http.StatusInternalServerError).
-					WithPayload(buildErrorPayload(err))
+					WithPayload(buildInternalErrorPayload(messages.ErrQueryAreas, err.Error()))
 			}
 		}
 		totalAreas := int64(total)
diff --git a/internal/handlers/category.go b/internal/handlers/category.go
index 124690ae..a51fabc9 100644
--- a/internal/handlers/category.go
+++ b/internal/handlers/category.go
@@ -12,6 +12,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/categories"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/repositories"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/utils"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
@@ -43,9 +44,9 @@ func (c *Category) CreateNewCategoryFunc(repository domain.CategoryRepository) c
 		ctx := s.HTTPRequest.Context()
 		createdCategory, err := repository.CreateCategory(ctx, *s.NewCategory)
 		if err != nil {
-			c.logger.Error("cant create new category", zap.Error(err))
+			c.logger.Error(messages.ErrCreateCategory, zap.Error(err))
 			return categories.NewCreateNewCategoryDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("cant create new category"))
+				WithPayload(buildInternalErrorPayload(messages.ErrCreateCategory, err.Error()))
 		}
 		return categories.NewCreateNewCategoryCreated().WithPayload(&models.CreateNewCategoryResponse{
 			Data: mapCategory(createdCategory),
@@ -63,9 +64,9 @@ func (c *Category) GetAllCategoriesFunc(repository domain.CategoryRepository) ca
 
 		total, err := repository.AllCategoriesTotal(ctx)
 		if err != nil {
-			c.logger.Error("query total categories error", zap.Error(err))
+			c.logger.Error(messages.ErrQueryTotalCategories, zap.Error(err))
 			return categories.NewGetAllCategoriesDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("cant get total amount of categories"))
+				WithPayload(buildInternalErrorPayload(messages.ErrQueryTotalCategories, err.Error()))
 		}
 		var allCategories []*ent.Category
 		if total > 0 {
@@ -82,9 +83,9 @@ func (c *Category) GetAllCategoriesFunc(repository domain.CategoryRepository) ca
 			}
 			allCategories, err = repository.AllCategories(ctx, filter)
 			if err != nil {
-				c.logger.Error("query all category error", zap.Error(err))
+				c.logger.Error(messages.ErrQueryCategories, zap.Error(err))
 				return categories.NewGetAllCategoriesDefault(http.StatusInternalServerError).
-					WithPayload(buildStringPayload("cant get all categories"))
+					WithPayload(buildInternalErrorPayload(messages.ErrQueryCategories, err.Error()))
 			}
 		}
 		mappedCategories := make([]*models.Category, len(allCategories))
@@ -105,9 +106,9 @@ func (c *Category) GetCategoryByIDFunc(repository domain.CategoryRepository) cat
 		ctx := s.HTTPRequest.Context()
 		category, err := repository.CategoryByID(ctx, int(s.CategoryID))
 		if err != nil {
-			c.logger.Error("failed to get category", zap.Error(err))
+			c.logger.Error(messages.ErrGetCategory, zap.Error(err))
 			return categories.NewGetCategoryByIDDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("failed to get category"))
+				WithPayload(buildInternalErrorPayload(messages.ErrGetCategory, err.Error()))
 		}
 		return categories.NewGetCategoryByIDOK().WithPayload(&models.GetCategoryByIDResponse{
 			Data: mapCategory(category),
@@ -120,11 +121,11 @@ func (c *Category) DeleteCategoryFunc(repository domain.CategoryRepository) cate
 		ctx := s.HTTPRequest.Context()
 		err := repository.DeleteCategoryByID(ctx, int(s.CategoryID))
 		if err != nil {
-			c.logger.Error("delete category failed", zap.Error(err))
+			c.logger.Error(messages.ErrDeleteCategory, zap.Error(err))
 			return categories.NewDeleteCategoryDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("delete category failed"))
+				WithPayload(buildInternalErrorPayload(messages.ErrDeleteCategory, err.Error()))
 		}
-		return categories.NewDeleteCategoryOK().WithPayload("category deleted")
+		return categories.NewDeleteCategoryOK().WithPayload(messages.MsgCategoryDeleted)
 	}
 }
 
@@ -133,9 +134,9 @@ func (c *Category) UpdateCategoryFunc(repository domain.CategoryRepository) cate
 		ctx := s.HTTPRequest.Context()
 		updatedCategory, err := repository.UpdateCategory(ctx, int(s.CategoryID), *s.UpdateCategory)
 		if err != nil {
-			c.logger.Error("cant update category", zap.Error(err))
+			c.logger.Error(messages.ErrUpdateCategory, zap.Error(err))
 			return categories.NewUpdateCategoryDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("cant update category"))
+				WithPayload(buildInternalErrorPayload(messages.ErrUpdateCategory, err.Error()))
 		}
 
 		return categories.NewUpdateCategoryOK().WithPayload(&models.UpdateCategoryResponse{
diff --git a/internal/handlers/common.go b/internal/handlers/common.go
index 666294cc..bbb92cff 100644
--- a/internal/handlers/common.go
+++ b/internal/handlers/common.go
@@ -1,19 +1,39 @@
 package handlers
 
-import "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
+import (
+	"net/http"
 
-func buildErrorPayload(err error) *models.Error {
-	return &models.Error{
-		Data: &models.ErrorData{
-			Message: err.Error(),
-		},
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
+)
+
+func buildErrorPayload(code int32, msg string, details string) *models.SwaggerError {
+	return &models.SwaggerError{
+		Code:    &code,
+		Message: &msg,
+		Details: details, // optional field for raw err messages
 	}
 }
 
-func buildStringPayload(msg string) *models.Error {
-	return &models.Error{
-		Data: &models.ErrorData{
-			Message: msg,
-		},
-	}
+func buildInternalErrorPayload(msg string, details string) *models.SwaggerError {
+	return buildErrorPayload(http.StatusInternalServerError, msg, details)
+}
+
+func buildExFailedErrorPayload(msg string, details string) *models.SwaggerError {
+	return buildErrorPayload(http.StatusExpectationFailed, msg, details)
+}
+
+func buildConflictErrorPayload(msg string, details string) *models.SwaggerError {
+	return buildErrorPayload(http.StatusConflict, msg, details)
+}
+
+func buildNotFoundErrorPayload(msg string, details string) *models.SwaggerError {
+	return buildErrorPayload(http.StatusNotFound, msg, details)
+}
+
+func buildForbiddenErrorPayload(msg string, details string) *models.SwaggerError {
+	return buildErrorPayload(http.StatusForbidden, msg, details)
+}
+
+func buildBadRequestErrorPayload(msg string, details string) *models.SwaggerError {
+	return buildErrorPayload(http.StatusBadRequest, msg, details)
 }
diff --git a/internal/handlers/email_confirm.go b/internal/handlers/email_confirm.go
index 9a342ec2..515d0539 100644
--- a/internal/handlers/email_confirm.go
+++ b/internal/handlers/email_confirm.go
@@ -3,8 +3,10 @@ package handlers
 import (
 	"net/http"
 
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/email_confirm"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
 	"github.com/go-openapi/runtime/middleware"
 	"go.uber.org/zap"
@@ -33,11 +35,12 @@ func (e emailConfirmHandler) VerifyEmailConfirmTokenFunc() email_confirm.VerifyE
 		token := s.Token
 		err := e.emailConfirm.VerifyTokenAndChangeEmail(ctx, token)
 		if err != nil {
-			e.logger.Error("Failed to verify email confirmation token", zap.Error(err))
+			e.logger.Error(messages.ErrEmailConfirm, zap.Error(err))
 			return email_confirm.NewVerifyEmailConfirmTokenDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Failed to verify email confirmation token. Please try again later"))
+				WithPayload(buildInternalErrorPayload(messages.ErrEmailConfirm, err.Error()))
 		}
 
-		return email_confirm.NewVerifyEmailConfirmTokenOK().WithPayload("You have successfully confirmed new email")
+		return email_confirm.NewVerifyEmailConfirmTokenOK().WithPayload(
+			models.EmailConfirmResponse(messages.MsgEmailConfirmed))
 	}
 }
diff --git a/internal/handlers/equipment.go b/internal/handlers/equipment.go
index fbb7b351..6043ff67 100644
--- a/internal/handlers/equipment.go
+++ b/internal/handlers/equipment.go
@@ -14,6 +14,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/equipment"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/repositories"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/roles"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/utils"
@@ -52,21 +53,21 @@ func (c Equipment) PostEquipmentFunc(eqRepo domain.EquipmentRepository, eqStatus
 		ctx := s.HTTPRequest.Context()
 		status, err := eqStatusNameRepo.GetByName(ctx, domain.EquipmentStatusAvailable)
 		if err != nil {
-			c.logger.Error("Error while getting status", zap.Error(err))
+			c.logger.Error(messages.ErrGetEqStatus, zap.Error(err))
 			return equipment.NewCreateNewEquipmentDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while creating equipment"))
+				WithPayload(buildInternalErrorPayload(messages.ErrCreateEquipment, err.Error()))
 		}
 		eq, err := eqRepo.CreateEquipment(ctx, *s.NewEquipment, status)
 		if err != nil {
-			c.logger.Error("Error while creating equipment", zap.Error(err))
+			c.logger.Error(messages.ErrCreateEquipment, zap.Error(err))
 			return equipment.NewCreateNewEquipmentDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while creating equipment"))
+				WithPayload(buildInternalErrorPayload(messages.ErrCreateEquipment, err.Error()))
 		}
 		returnEq, err := mapEquipmentResponse(eq)
 		if err != nil {
-			c.logger.Error("Error while mapping equipment", zap.Error(err))
+			c.logger.Error(messages.ErrMapEquipment, zap.Error(err))
 			return equipment.NewCreateNewEquipmentDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while mapping equipment"))
+				WithPayload(buildInternalErrorPayload(messages.ErrMapEquipment, err.Error()))
 		}
 
 		return equipment.NewCreateNewEquipmentCreated().WithPayload(returnEq)
@@ -78,15 +79,15 @@ func (c Equipment) GetEquipmentFunc(repository domain.EquipmentRepository) equip
 		ctx := s.HTTPRequest.Context()
 		eq, err := repository.EquipmentByID(ctx, int(s.EquipmentID))
 		if err != nil {
-			c.logger.Error("Error while getting equipment", zap.Error(err))
+			c.logger.Error(messages.ErrGetEquipment, zap.Error(err))
 			return equipment.NewGetEquipmentDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while getting equipment"))
+				WithPayload(buildInternalErrorPayload(messages.ErrGetEquipment, err.Error()))
 		}
 		returnEq, err := mapEquipmentResponse(eq)
 		if err != nil {
-			c.logger.Error("Error while mapping equipment", zap.Error(err))
+			c.logger.Error(messages.ErrMapEquipment, zap.Error(err))
 			return equipment.NewGetEquipmentDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while mapping equipment"))
+				WithPayload(buildInternalErrorPayload(messages.ErrMapEquipment, err.Error()))
 		}
 		return equipment.NewGetEquipmentOK().WithPayload(returnEq)
 	}
@@ -99,11 +100,11 @@ func (c Equipment) ArchiveEquipmentFunc(repository domain.EquipmentRepository) e
 		if err != nil {
 			if ent.IsNotFound(err) {
 				return equipment.NewArchiveEquipmentNotFound().
-					WithPayload(buildStringPayload(EquipmentNotFoundMsg))
+					WithPayload(buildNotFoundErrorPayload(messages.ErrEquipmentNotFound, ""))
 			}
-			c.logger.Error("Error while archiving equipment", zap.Error(err))
+			c.logger.Error(messages.ErrEquipmentArchive, zap.Error(err))
 			return equipment.NewArchiveEquipmentDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while archiving equipment"))
+				WithPayload(buildInternalErrorPayload(messages.ErrEquipmentArchive, err.Error()))
 		}
 		return equipment.NewArchiveEquipmentNoContent()
 	}
@@ -114,25 +115,22 @@ func (c Equipment) DeleteEquipmentFunc(repository domain.EquipmentRepository) eq
 		ctx := s.HTTPRequest.Context()
 		eq, err := repository.EquipmentByID(ctx, int(s.EquipmentID))
 		if err != nil {
-			c.logger.Error("Error while getting equipment", zap.Error(err))
-			return equipment.NewDeleteEquipmentDefault(http.StatusInternalServerError).WithPayload(&models.Error{
-				Data: &models.ErrorData{
-					Message: "Error while getting equipment",
-				},
-			})
+			c.logger.Error(messages.ErrGetEquipment, zap.Error(err))
+			return equipment.NewDeleteEquipmentDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrDeleteEquipment, err.Error()))
 		}
 		err = repository.DeleteEquipmentByID(ctx, int(s.EquipmentID))
 		if err != nil {
-			c.logger.Error("Error while deleting equipment", zap.Error(err))
+			c.logger.Error(messages.ErrDeleteEquipment, zap.Error(err))
 			return equipment.NewDeleteEquipmentDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while deleting equipment"))
+				WithPayload(buildInternalErrorPayload(messages.ErrDeleteEquipment, err.Error()))
 		}
 
 		if err := repository.DeleteEquipmentPhoto(ctx, eq.Edges.Photo.ID); err != nil {
 			c.logger.Error("Error while deleting photo from db", zap.Error(err))
 		}
 
-		return equipment.NewDeleteEquipmentOK().WithPayload("Equipment deleted")
+		return equipment.NewDeleteEquipmentOK().WithPayload(messages.MsgEquipmentDeleted)
 	}
 }
 
@@ -145,17 +143,17 @@ func (c Equipment) ListEquipmentFunc(repository domain.EquipmentRepository) equi
 		orderColumn := utils.GetValueByPointerOrDefaultValue(s.OrderColumn, order.FieldID)
 		total, err := repository.AllEquipmentsTotal(ctx)
 		if err != nil {
-			c.logger.Error("Error while getting total of all equipments", zap.Error(err))
+			c.logger.Error(messages.ErrQueryTotalEquipments, zap.Error(err))
 			return equipment.NewGetAllEquipmentDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while getting total of all equipments"))
+				WithPayload(buildInternalErrorPayload(messages.ErrQueryTotalEquipments, err.Error()))
 		}
 		var equipments []*ent.Equipment
 		if total > 0 {
 			equipments, err = repository.AllEquipments(ctx, int(limit), int(offset), orderBy, orderColumn)
 			if err != nil {
-				c.logger.Error("Error while getting all equipments", zap.Error(err))
+				c.logger.Error(messages.ErrQueryEquipments, zap.Error(err))
 				return equipment.NewGetAllEquipmentDefault(http.StatusInternalServerError).
-					WithPayload(buildStringPayload("Error while getting all equipments"))
+					WithPayload(buildInternalErrorPayload(messages.ErrQueryEquipments, err.Error()))
 			}
 		}
 		totalEquipments := int64(total)
@@ -166,9 +164,9 @@ func (c Equipment) ListEquipmentFunc(repository domain.EquipmentRepository) equi
 		for i, eq := range equipments {
 			tmpEq, errMap := mapEquipmentResponse(eq)
 			if errMap != nil {
-				c.logger.Error("Error while mapping equipment", zap.Error(errMap))
+				c.logger.Error(messages.ErrMapEquipment, zap.Error(errMap))
 				return equipment.NewGetAllEquipmentDefault(http.StatusInternalServerError).
-					WithPayload(buildStringPayload("Error while mapping equipment"))
+					WithPayload(buildInternalErrorPayload(messages.ErrMapEquipment, errMap.Error()))
 			}
 			listEquipment.Items[i] = tmpEq
 		}
@@ -181,15 +179,15 @@ func (c Equipment) EditEquipmentFunc(repository domain.EquipmentRepository) equi
 		ctx := s.HTTPRequest.Context()
 		eq, err := repository.UpdateEquipmentByID(ctx, int(s.EquipmentID), s.EditEquipment)
 		if err != nil {
-			c.logger.Error("Error while updating equipment", zap.Error(err))
+			c.logger.Error(messages.ErrUpdateEquipment, zap.Error(err))
 			return equipment.NewEditEquipmentDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while updating equipment"))
+				WithPayload(buildInternalErrorPayload(messages.ErrUpdateEquipment, err.Error()))
 		}
 		returnEq, err := mapEquipmentResponse(eq)
 		if err != nil {
-			c.logger.Error("Error while mapping equipment", zap.Error(err))
+			c.logger.Error(messages.ErrMapEquipment, zap.Error(err))
 			return equipment.NewEditEquipmentDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while mapping equipment"))
+				WithPayload(buildInternalErrorPayload(messages.ErrMapEquipment, err.Error()))
 		}
 
 		return equipment.NewEditEquipmentOK().WithPayload(returnEq)
@@ -206,17 +204,17 @@ func (c Equipment) FindEquipmentFunc(repository domain.EquipmentRepository) equi
 		equipmentFilter := *s.FindEquipment
 		total, err := repository.EquipmentsByFilterTotal(ctx, equipmentFilter)
 		if err != nil {
-			c.logger.Error("Error while getting total of all equipments", zap.Error(err))
+			c.logger.Error(messages.ErrQueryTotalEquipments, zap.Error(err))
 			return equipment.NewGetAllEquipmentDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while getting total of all equipments"))
+				WithPayload(buildInternalErrorPayload(messages.ErrQueryTotalEquipments, err.Error()))
 		}
 		var foundEquipment []*ent.Equipment
 		if total > 0 {
 			foundEquipment, err = repository.EquipmentsByFilter(ctx, equipmentFilter, int(limit), int(offset), orderBy, orderColumn)
 			if err != nil {
-				c.logger.Error("Error while finding equipment", zap.Error(err))
+				c.logger.Error(messages.ErrFindEquipment, zap.Error(err))
 				return equipment.NewFindEquipmentDefault(http.StatusInternalServerError).
-					WithPayload(buildStringPayload("Error while finding equipment"))
+					WithPayload(buildInternalErrorPayload(messages.ErrFindEquipment, err.Error()))
 			}
 		}
 		totalEquipments := int64(total)
@@ -227,9 +225,9 @@ func (c Equipment) FindEquipmentFunc(repository domain.EquipmentRepository) equi
 		for i, eq := range foundEquipment {
 			tmpEq, errMap := mapEquipmentResponse(eq)
 			if errMap != nil {
-				c.logger.Error("Error while mapping equipment", zap.Error(errMap))
+				c.logger.Error(messages.ErrMapEquipment, zap.Error(errMap))
 				return equipment.NewFindEquipmentDefault(http.StatusInternalServerError).
-					WithPayload(buildStringPayload("Error while mapping equipment"))
+					WithPayload(buildInternalErrorPayload(messages.ErrMapEquipment, errMap.Error()))
 			}
 			returnEquipment.Items[i] = tmpEq
 		}
@@ -314,21 +312,25 @@ func (c Equipment) BlockEquipmentFunc(repository domain.EquipmentRepository) equ
 			c.logger.Warn("User have no right to block the equipment", zap.Any("principal", principal))
 			return equipment.
 				NewBlockEquipmentDefault(http.StatusForbidden).
-				WithPayload(&models.Error{Data: &models.ErrorData{
-					Message: "You don't have rights to block the equipment"}})
+				WithPayload(buildForbiddenErrorPayload(messages.ErrEquipmentBlockForbidden, ""))
+		}
+
+		startDate := time.Time(s.Data.StartDate)
+		endDate := time.Time(s.Data.EndDate)
+		if startDate.After(endDate) {
+			return equipment.NewBlockEquipmentDefault(http.StatusBadRequest).
+				WithPayload(buildBadRequestErrorPayload(messages.ErrStartDateAfterEnd, ""))
 		}
 
-		err := repository.BlockEquipment(
-			ctx, int(s.EquipmentID), time.Time(s.Data.StartDate), time.Time(s.Data.EndDate), userID,
-		)
+		err := repository.BlockEquipment(ctx, int(s.EquipmentID), startDate, endDate, userID)
 		if err != nil {
 			if ent.IsNotFound(err) {
 				return equipment.NewBlockEquipmentNotFound().
-					WithPayload(buildStringPayload(EquipmentNotFoundMsg))
+					WithPayload(buildNotFoundErrorPayload(messages.ErrEquipmentNotFound, ""))
 			}
-			c.logger.Error("Error while blocking equipment", zap.Error(err))
+			c.logger.Error(messages.ErrEquipmentBlock, zap.Error(err))
 			return equipment.NewBlockEquipmentDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while blocking equipment"))
+				WithPayload(buildInternalErrorPayload(messages.ErrEquipmentBlock, err.Error()))
 		}
 		return equipment.NewBlockEquipmentNoContent()
 	}
@@ -340,21 +342,21 @@ func (c Equipment) UnblockEquipmentFunc(repository domain.EquipmentRepository) e
 		role := principal.Role
 
 		if role != roles.Manager {
-			c.logger.Warn("User have no right to unblock the equipment", zap.Any("principal", principal))
+			c.logger.Warn(messages.ErrEquipmentUnblockForbidden, zap.Any("principal", principal))
 			return equipment.
 				NewUnblockEquipmentDefault(http.StatusForbidden).
-				WithPayload(buildStringPayload("You don't have rights to unblock the equipment"))
+				WithPayload(buildForbiddenErrorPayload(messages.ErrEquipmentUnblockForbidden, ""))
 		}
 
 		err := repository.UnblockEquipment(ctx, int(s.EquipmentID))
 		if err != nil {
 			if ent.IsNotFound(err) {
 				return equipment.NewUnblockEquipmentNotFound().
-					WithPayload(buildStringPayload(EquipmentNotFoundMsg))
+					WithPayload(buildNotFoundErrorPayload(messages.ErrEquipmentNotFound, ""))
 			}
-			c.logger.Error("Error while unblocking equipment", zap.Error(err))
+			c.logger.Error(messages.ErrEquipmentUnblock, zap.Error(err))
 			return equipment.NewUnblockEquipmentDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while unblocking equipment"))
+				WithPayload(buildInternalErrorPayload(messages.ErrEquipmentUnblock, err.Error()))
 		}
 		return equipment.NewUnblockEquipmentNoContent()
 	}
diff --git a/internal/handlers/equipment_periods.go b/internal/handlers/equipment_periods.go
index 4d7b9520..51281a8f 100644
--- a/internal/handlers/equipment_periods.go
+++ b/internal/handlers/equipment_periods.go
@@ -7,6 +7,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations"
 	eqPeriods "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/equipment"
 	eqStatus "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/equipment_status"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/repositories"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
 	"github.com/go-openapi/runtime/middleware"
@@ -44,12 +45,9 @@ func (c EquipmentPeriods) GetEquipmentUnavailableDatesFunc(
 
 		equipmentStatuses, err := eqStatusRepository.GetUnavailableEquipmentStatusByEquipmentID(ctx, id)
 		if err != nil {
-			c.logger.Error(
-				"error during the search for unavailable equipment status dates",
-				zap.Error(err),
-			)
+			c.logger.Error(messages.ErrGetUnavailableEqStatus, zap.Error(err))
 			return eqStatus.NewCheckEquipmentStatusDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("can't find unavailable equipment status dates"))
+				WithPayload(buildInternalErrorPayload(messages.ErrGetUnavailableEqStatus, err.Error()))
 		}
 
 		var result []*models.EquipmentUnavailabilityPeriods
diff --git a/internal/handlers/equipment_status.go b/internal/handlers/equipment_status.go
index 49543713..c6e4eddd 100644
--- a/internal/handlers/equipment_status.go
+++ b/internal/handlers/equipment_status.go
@@ -8,6 +8,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations"
 	eqStatus "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/equipment_status"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/orders"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/repositories"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
 	"github.com/go-openapi/runtime/middleware"
@@ -51,9 +52,9 @@ func (c EquipmentStatus) GetEquipmentStatusCheckDatesFunc(
 		newStatus := s.Name.StatusName
 
 		if !newStatusIsUnavailable(*newStatus) {
-			c.logger.Error("Wrong new equipment status, status should be only 'not available'", zap.Any("principal", principal))
-			return orders.NewAddNewOrderStatusDefault(http.StatusForbidden).
-				WithPayload(&models.Error{Data: &models.ErrorData{Message: "Wrong new equipment status, status should be only 'not available'"}})
+			c.logger.Error(messages.ErrWrongEqStatus, zap.Any("principal", principal))
+			return orders.NewAddNewOrderStatusDefault(http.StatusBadRequest).
+				WithPayload(buildBadRequestErrorPayload(messages.ErrWrongEqStatus, ""))
 		}
 
 		data := models.EquipmentStatus{
@@ -68,7 +69,7 @@ func (c EquipmentStatus) GetEquipmentStatusCheckDatesFunc(
 		if err != nil {
 			c.logger.Error("receiving equipment status by id failed during checking start/end dates", zap.Error(err))
 			return eqStatus.NewCheckEquipmentStatusDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("can't find equipment status by provided id"))
+				WithPayload(buildInternalErrorPayload(messages.ErrGetEqStatusByID, err.Error()))
 		}
 
 		if !eqStatusResult.EndDate.After(time.Time(*data.StartDate)) &&
@@ -81,9 +82,9 @@ func (c EquipmentStatus) GetEquipmentStatusCheckDatesFunc(
 		orderResult, userResult, err := eqStatusRepository.GetOrderAndUserByEquipmentStatusID(
 			ctx, int(*data.ID))
 		if err != nil {
-			c.logger.Error("receiving order and user data failed", zap.Error(err))
+			c.logger.Error(messages.ErrOrderAndUserByEqStatusID, zap.Error(err))
 			return eqStatus.NewCheckEquipmentStatusDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("can't receive order and user data during checking equipment status"))
+				WithPayload(buildInternalErrorPayload(messages.ErrOrderAndUserByEqStatusID, err.Error()))
 		}
 
 		if orderResult == nil && userResult == nil {
@@ -116,9 +117,9 @@ func (c EquipmentStatus) PutEquipmentStatusInRepairFunc(
 		newStatus := s.Name.StatusName
 
 		if !newStatusIsUnavailable(*newStatus) {
-			c.logger.Error("Wrong new equipment status, status should be only 'not available'", zap.Any("principal", principal))
-			return orders.NewAddNewOrderStatusDefault(http.StatusForbidden).
-				WithPayload(&models.Error{Data: &models.ErrorData{Message: "Wrong new equipment status, status should be only 'not available'"}})
+			c.logger.Error(messages.ErrWrongEqStatus, zap.Any("principal", principal))
+			return orders.NewAddNewOrderStatusDefault(http.StatusBadRequest).
+				WithPayload(buildBadRequestErrorPayload(messages.ErrWrongEqStatus, ""))
 		}
 
 		reduceOneDayFromCurrentStartDate := strfmt.DateTime(
@@ -139,16 +140,16 @@ func (c EquipmentStatus) PutEquipmentStatusInRepairFunc(
 		orderResult, userResult, err := eqStatusRepository.GetOrderAndUserByEquipmentStatusID(
 			ctx, int(*data.ID))
 		if err != nil {
-			c.logger.Error("receiving user and order status failed", zap.Error(err))
+			c.logger.Error(messages.ErrOrderAndUserByEqStatusID, zap.Error(err))
 			return eqStatus.NewUpdateEquipmentStatusOnUnavailableDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("can't receive order and user for updating equipment status on unavailable"))
+				WithPayload(buildInternalErrorPayload(messages.ErrOrderAndUserByEqStatusID, err.Error()))
 		}
 
 		updatedEqStatus, err := eqStatusRepository.Update(ctx, &data)
 		if err != nil {
-			c.logger.Error("update equipment status failed", zap.Error(err))
+			c.logger.Error(messages.ErrUpdateEqStatus, zap.Error(err))
 			return eqStatus.NewUpdateEquipmentStatusOnUnavailableDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("can't update equipment status"))
+				WithPayload(buildInternalErrorPayload(messages.ErrUpdateEqStatus, err.Error()))
 		}
 
 		comment := EQUIPMENT_UNDER_REPAIR_COMMENT_FOR_ORDER
@@ -163,9 +164,9 @@ func (c EquipmentStatus) PutEquipmentStatusInRepairFunc(
 
 		err = orderStatusRepo.UpdateStatus(ctx, userResult.ID, model)
 		if err != nil {
-			c.logger.Error("Update order status error", zap.Error(err))
+			c.logger.Error(messages.ErrUpdateOrderStatus, zap.Error(err))
 			return orders.NewAddNewOrderStatusDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Can't update order status"))
+				WithPayload(buildInternalErrorPayload(messages.ErrUpdateOrderStatus, err.Error()))
 		}
 
 		eqStatusResult, err := eqStatusRepository.GetEquipmentStatusByID(
@@ -173,7 +174,7 @@ func (c EquipmentStatus) PutEquipmentStatusInRepairFunc(
 		if err != nil {
 			c.logger.Error("receiving equipment status by id failed during changing status to unavailable", zap.Error(err))
 			return eqStatus.NewCheckEquipmentStatusDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("can't find equipment status by provided id"))
+				WithPayload(buildInternalErrorPayload(messages.ErrGetEqStatusByID, err.Error()))
 		}
 
 		equipmentStatusID := int64(updatedEqStatus.ID)
@@ -200,9 +201,9 @@ func (c EquipmentStatus) DeleteEquipmentStatusFromRepairFunc(
 		newStatus := s.Name.StatusName
 
 		if !newStatusIsAvailable(*newStatus) {
-			c.logger.Error("Wrong new equipment status, status should be only 'available'", zap.Any("principal", principal))
-			return orders.NewAddNewOrderStatusDefault(http.StatusForbidden).
-				WithPayload(&models.Error{Data: &models.ErrorData{Message: "Wrong new equipment status, status should be only 'not available'"}})
+			c.logger.Error(messages.ErrWrongEqStatus, zap.Any("principal", principal))
+			return orders.NewAddNewOrderStatusDefault(http.StatusBadGateway).
+				WithPayload(buildBadRequestErrorPayload(messages.ErrWrongEqStatus, ""))
 		}
 
 		timeNow := timeNowEquipmentStatus()
@@ -219,7 +220,7 @@ func (c EquipmentStatus) DeleteEquipmentStatusFromRepairFunc(
 		if err != nil {
 			c.logger.Error("update equipment on available status failed", zap.Error(err))
 			return eqStatus.NewUpdateEquipmentStatusOnAvailableDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("can't update equipment status on available status"))
+				WithPayload(buildInternalErrorPayload(messages.ErrUpdateEqStatus, err.Error()))
 		}
 
 		eqStatusResult, err := eqStatusRepository.GetEquipmentStatusByID(
@@ -227,7 +228,7 @@ func (c EquipmentStatus) DeleteEquipmentStatusFromRepairFunc(
 		if err != nil {
 			c.logger.Error("receiving equipment status by id failed during changing status to available", zap.Error(err))
 			return eqStatus.NewCheckEquipmentStatusDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("can't find equipment status by provided id"))
+				WithPayload(buildInternalErrorPayload(messages.ErrGetEqStatusByID, err.Error()))
 		}
 
 		equipmentStatusID := int64(updatedEqStatus.ID)
@@ -257,7 +258,7 @@ func (c EquipmentStatus) PatchEquipmentStatusEditDatesFunc(
 		if err != nil {
 			c.logger.Error("receiving equipment status by id failed during editing dates", zap.Error(err))
 			return eqStatus.NewCheckEquipmentStatusDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("can't find equipment status by provided id"))
+				WithPayload(buildInternalErrorPayload(messages.ErrGetEqStatusByID, err.Error()))
 		}
 
 		if !time.Time(s.Name.StartDate).IsZero() {
@@ -278,7 +279,7 @@ func (c EquipmentStatus) PatchEquipmentStatusEditDatesFunc(
 		if err != nil {
 			c.logger.Error("update equipment on available status failed during editing dates", zap.Error(err))
 			return eqStatus.NewUpdateRepairedEquipmentStatusDatesDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("can't update equipment status on available status during editing dates"))
+				WithPayload(buildInternalErrorPayload(messages.ErrUpdateEqStatus, err.Error()))
 		}
 
 		equipmentStatusID := int64(updatedEqStatus.ID)
diff --git a/internal/handlers/equipment_status_name.go b/internal/handlers/equipment_status_name.go
index 1fd80adb..bd859228 100644
--- a/internal/handlers/equipment_status_name.go
+++ b/internal/handlers/equipment_status_name.go
@@ -10,6 +10,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations"
 	eqStatusName "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/equipment_status_name"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/repositories"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
 )
@@ -40,9 +41,9 @@ func (c EquipmentStatusName) PostEquipmentStatusNameFunc(repository domain.Equip
 		name := s.Name.Name
 		createdStatus, err := repository.Create(ctx, *name)
 		if err != nil {
-			c.logger.Error("create status failed", zap.Error(err))
+			c.logger.Error(messages.ErrCreateEqStatus, zap.Error(err))
 			return eqStatusName.NewPostEquipmentStatusNameDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("can't create status"))
+				WithPayload(buildInternalErrorPayload(messages.ErrCreateEqStatus, err.Error()))
 		}
 
 		return eqStatusName.NewPostEquipmentStatusNameCreated().WithPayload(&models.SuccessEquipmentStatusNameOperationResponse{
@@ -56,9 +57,9 @@ func (c EquipmentStatusName) ListEquipmentStatusNamesFunc(repository domain.Equi
 		ctx := s.HTTPRequest.Context()
 		statuses, err := repository.GetAll(ctx)
 		if err != nil {
-			c.logger.Error("get statuses failed", zap.Error(err))
+			c.logger.Error(messages.ErrQueryEqStatuses, zap.Error(err))
 			return eqStatusName.NewListEquipmentStatusNamesDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("can't get statuses"))
+				WithPayload(buildInternalErrorPayload(messages.ErrQueryEqStatuses, err.Error()))
 		}
 		listStatuses := models.ListEquipmentStatusNames{}
 		for _, element := range statuses {
@@ -73,9 +74,9 @@ func (c EquipmentStatusName) GetEquipmentStatusNameFunc(repository domain.Equipm
 		ctx := s.HTTPRequest.Context()
 		foundStatus, err := repository.Get(ctx, int(s.StatusID))
 		if err != nil {
-			c.logger.Error("get status failed", zap.Error(err))
+			c.logger.Error(messages.ErrGetEqStatus, zap.Error(err))
 			return eqStatusName.NewGetEquipmentStatusNameDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("can't get status"))
+				WithPayload(buildInternalErrorPayload(messages.ErrGetEqStatus, err.Error()))
 		}
 
 		return eqStatusName.NewGetEquipmentStatusNameOK().WithPayload(&models.SuccessEquipmentStatusNameOperationResponse{
@@ -89,9 +90,9 @@ func (c EquipmentStatusName) DeleteEquipmentStatusNameFunc(repository domain.Equ
 		ctx := s.HTTPRequest.Context()
 		deletedStatus, err := repository.Delete(ctx, int(s.StatusID))
 		if err != nil {
-			c.logger.Error("delete status failed", zap.Error(err))
+			c.logger.Error(messages.ErrDeleteEqStatus, zap.Error(err))
 			return eqStatusName.NewDeleteEquipmentStatusNameDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("can't delete status"))
+				WithPayload(buildInternalErrorPayload(messages.ErrDeleteEqStatus, err.Error()))
 		}
 		return eqStatusName.NewDeleteEquipmentStatusNameOK().WithPayload(
 			&models.SuccessEquipmentStatusNameOperationResponse{
diff --git a/internal/handlers/order.go b/internal/handlers/order.go
index d721249c..516e6827 100644
--- a/internal/handlers/order.go
+++ b/internal/handlers/order.go
@@ -16,6 +16,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/orders"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/repositories"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/utils"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
@@ -221,30 +222,32 @@ func (o Order) ListUserOrdersFunc(repository domain.OrderRepository) orders.GetU
 			_, ok := domain.AllOrderStatuses[*p.Status]
 			if !ok {
 				return orders.NewGetUserOrdersDefault(http.StatusBadRequest).
-					WithPayload(buildStringPayload(fmt.Sprintf("Invalid order status '%v'", *p.Status)))
+					WithPayload(buildBadRequestErrorPayload(messages.ErrQueryOrders, fmt.Sprintf("invalid order status '%v'", *p.Status)))
 			}
 		}
 
 		total, err := repository.OrdersTotal(ctx, &userID)
 		if err != nil {
-			o.logger.Error("Error while getting total of all user's orders", zap.Error(err))
+			o.logger.Error(messages.ErrQueryTotalOrders, zap.Error(err))
 			return orders.NewGetUserOrdersDefault(http.StatusInternalServerError).
-				WithPayload(buildErrorPayload(err))
+				WithPayload(buildBadRequestErrorPayload(messages.ErrQueryTotalOrders, err.Error()))
 		}
 
 		var items []*ent.Order
 		if total > 0 {
 			items, err = repository.List(ctx, &userID, orderFilter)
 			if err != nil {
-				o.logger.Error("list items failed", zap.Error(err))
-				return orders.NewGetUserOrdersDefault(http.StatusInternalServerError).WithPayload(buildErrorPayload(err))
+				o.logger.Error(messages.ErrQueryOrders, zap.Error(err))
+				return orders.NewGetUserOrdersDefault(http.StatusInternalServerError).
+					WithPayload(buildBadRequestErrorPayload(messages.ErrQueryOrders, err.Error()))
 			}
 		}
 
 		mappedOrders, err := mapUserOrdersToResponse(items, o.logger)
 		if err != nil {
-			o.logger.Error("map orders to response failed", zap.Error(err))
-			return orders.NewGetUserOrdersDefault(http.StatusInternalServerError).WithPayload(buildErrorPayload(err))
+			o.logger.Error(messages.ErrMapOrder, zap.Error(err))
+			return orders.NewGetUserOrdersDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrMapOrder, err.Error()))
 		}
 		totalOrders := int64(total)
 		listOrders := &models.UserOrdersList{
@@ -276,7 +279,7 @@ func (o Order) ListAllOrdersFunc(repository domain.OrderRepository) orders.GetAl
 			_, ok := domain.AllOrderStatuses[*p.Status]
 			if !ok {
 				return orders.NewGetAllOrdersDefault(http.StatusBadRequest).
-					WithPayload(buildStringPayload(fmt.Sprintf("Invalid order status '%v'", *p.Status)))
+					WithPayload(buildBadRequestErrorPayload(messages.ErrQueryOrders, fmt.Sprintf("invalid order status '%v'", *p.Status)))
 			}
 			orderFilter.Status = p.Status
 		}
@@ -288,24 +291,26 @@ func (o Order) ListAllOrdersFunc(repository domain.OrderRepository) orders.GetAl
 
 		total, err := repository.OrdersTotal(ctx, nil)
 		if err != nil {
-			o.logger.Error("Error while getting total of all orders", zap.Error(err))
+			o.logger.Error(messages.ErrQueryTotalOrders, zap.Error(err))
 			return orders.NewGetAllOrdersDefault(http.StatusInternalServerError).
-				WithPayload(buildErrorPayload(err))
+				WithPayload(buildInternalErrorPayload(messages.ErrQueryTotalOrders, err.Error()))
 		}
 
 		var items []*ent.Order
 		if total > 0 {
 			items, err = repository.List(ctx, nil, orderFilter)
 			if err != nil {
-				o.logger.Error("list items failed", zap.Error(err))
-				return orders.NewGetAllOrdersDefault(http.StatusInternalServerError).WithPayload(buildErrorPayload(err))
+				o.logger.Error(messages.ErrQueryOrders, zap.Error(err))
+				return orders.NewGetAllOrdersDefault(http.StatusInternalServerError).
+					WithPayload(buildInternalErrorPayload(messages.ErrQueryOrders, err.Error()))
 			}
 		}
 
 		mappedOrders, err := mapOrdersToResponse(items, o.logger)
 		if err != nil {
-			o.logger.Error("map orders to response failed", zap.Error(err))
-			return orders.NewGetAllOrdersDefault(http.StatusInternalServerError).WithPayload(buildErrorPayload(err))
+			o.logger.Error(messages.ErrMapOrder, zap.Error(err))
+			return orders.NewGetAllOrdersDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrMapOrder, err.Error()))
 		}
 		totalOrders := int64(total)
 		listOrders := &models.OrdersList{
@@ -329,20 +334,35 @@ func (o Order) CreateOrderFunc(
 		isEquipmentAvailable, err := eqStatusRepo.HasStatusByPeriod(ctx, domain.EquipmentStatusAvailable, id,
 			time.Time(*p.Data.RentStart), time.Time(*p.Data.RentEnd))
 		if err != nil {
-			o.logger.Error("error while checking if equipment is available for period", zap.Error(err))
-			return orders.NewCreateOrderDefault(http.StatusInternalServerError).WithPayload(buildErrorPayload(err))
+			o.logger.Error(messages.ErrCheckEqStatusFailed, zap.Error(err))
+			return orders.NewCreateOrderDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrCheckEqStatusFailed, err.Error()))
 		}
 
 		if !isEquipmentAvailable {
-			o.logger.Warn("equipment is not free")
-			return orders.NewCreateOrderDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("requested equipment is not free"))
+			o.logger.Warn(messages.ErrEquipmentIsNotFree)
+			return orders.NewCreateOrderDefault(http.StatusConflict).
+				WithPayload(buildConflictErrorPayload(messages.ErrEquipmentIsNotFree, ""))
+		}
+
+		rentStart := time.Time(*p.Data.RentStart)
+		rentEnd := time.Time(*p.Data.RentEnd)
+
+		if rentStart.After(rentEnd) {
+			return orders.NewCreateOrderDefault(http.StatusBadRequest).
+				WithPayload(buildBadRequestErrorPayload(messages.ErrStartDateAfterEnd, ""))
+		}
+
+		if rentEnd.Sub(rentStart).Hours() < 24 {
+			return orders.NewCreateOrderDefault(http.StatusBadRequest).
+				WithPayload(buildBadRequestErrorPayload(messages.ErrSmallRentPeriod, ""))
 		}
 
 		order, err := orderRepo.Create(ctx, p.Data, userID, []int{id})
 		if err != nil {
-			o.logger.Error("map orders to response failed", zap.Error(err))
-			return orders.NewCreateOrderDefault(http.StatusInternalServerError).WithPayload(buildErrorPayload(err))
+			o.logger.Error(messages.ErrMapOrder, zap.Error(err))
+			return orders.NewCreateOrderDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrMapOrder, err.Error()))
 		}
 
 		equipmentBookedStartDate := strfmt.DateTime(time.Time(*p.Data.RentStart).AddDate(0, 0, -1))
@@ -355,15 +375,16 @@ func (o Order) CreateOrderFunc(
 			StatusName:  &domain.EquipmentStatusBooked,
 			OrderID:     int64(order.ID),
 		}); err != nil {
-			o.logger.Error("error while creating equipment status", zap.Error(err))
-			return orders.NewGetUserOrdersDefault(http.StatusInternalServerError).
-				WithPayload(buildErrorPayload(err))
+			o.logger.Error(messages.ErrCreateEqStatus, zap.Error(err))
+			return orders.NewGetAllOrdersDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrCreateEqStatus, err.Error()))
 		}
 
 		mappedOrder, err := mapUserOrder(order, o.logger)
 		if err != nil {
-			o.logger.Error("failed to map order", zap.Error(err))
-			return orders.NewGetUserOrdersDefault(http.StatusInternalServerError).WithPayload(buildErrorPayload(err))
+			o.logger.Error(messages.ErrMapOrder, zap.Error(err))
+			return orders.NewGetAllOrdersDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrMapOrder, err.Error()))
 		}
 
 		return orders.NewCreateOrderCreated().WithPayload(mappedOrder)
@@ -378,14 +399,16 @@ func (o Order) UpdateOrderFunc(repository domain.OrderRepository) orders.UpdateO
 
 		order, err := repository.Update(ctx, orderID, p.Data, userID)
 		if err != nil {
-			o.logger.Error("update order failed", zap.Error(err))
-			return orders.NewUpdateOrderDefault(http.StatusInternalServerError).WithPayload(buildErrorPayload(err))
+			o.logger.Error(messages.ErrUpdateOrder, zap.Error(err))
+			return orders.NewUpdateOrderDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrUpdateOrder, err.Error()))
 		}
 
 		mappedOrder, err := mapUserOrder(order, o.logger)
 		if err != nil {
-			o.logger.Error("failed to map order", zap.Error(err))
-			return orders.NewUpdateOrderDefault(http.StatusInternalServerError).WithPayload(buildErrorPayload(err))
+			o.logger.Error(messages.ErrMapOrder, zap.Error(err))
+			return orders.NewUpdateOrderDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrMapOrder, err.Error()))
 		}
 
 		return orders.NewUpdateOrderOK().WithPayload(mappedOrder)
diff --git a/internal/handlers/order_status.go b/internal/handlers/order_status.go
index 3df522e3..bf2243fb 100644
--- a/internal/handlers/order_status.go
+++ b/internal/handlers/order_status.go
@@ -17,6 +17,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/orders"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/repositories"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/roles"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/utils"
@@ -59,17 +60,18 @@ func (h *OrderStatus) OrderStatusesHistory(repository domain.OrderStatusReposito
 		history, err := repository.StatusHistory(ctx, orderID)
 		if err != nil {
 			h.logger.Error("ListOrderStatus error", zap.Error(err))
-			return orders.NewGetFullOrderHistoryDefault(http.StatusInternalServerError).WithPayload(buildErrorPayload(err))
+			return orders.NewGetFullOrderHistoryDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrQueryOrderHistory, err.Error()))
 		}
 
 		if !canUserAccessOrderHistory(userID, role, history) {
 			h.logger.Warn("User have no right to get order history", zap.Any("principal", principal))
 			return orders.NewGetFullOrderHistoryDefault(http.StatusForbidden).
-				WithPayload(&models.Error{Data: &models.ErrorData{Message: "You don't have rights to see this order"}})
+				WithPayload(buildForbiddenErrorPayload(messages.ErrQueryOrderHistoryForbidden, ""))
 		}
 		if len(history) == 0 {
-			h.logger.Info("No order with such id", zap.Int("order_id", orderID))
-			return orders.NewGetFullOrderHistoryNotFound().WithPayload("No order with such id")
+			h.logger.Info(messages.ErrOrderNotFound, zap.Int("order_id", orderID))
+			return orders.NewGetFullOrderHistoryNotFound().WithPayload(messages.ErrOrderNotFound)
 		}
 		result := make([]*models.OrderStatus, len(history))
 		for index, status := range history {
@@ -77,7 +79,8 @@ func (h *OrderStatus) OrderStatusesHistory(repository domain.OrderStatusReposito
 			if mapErr != nil {
 				h.logger.Error("ListOrderStatus error", zap.Error(mapErr))
 
-				return orders.NewGetFullOrderHistoryDefault(http.StatusInternalServerError).WithPayload(buildErrorPayload(mapErr))
+				return orders.NewGetFullOrderHistoryDefault(http.StatusInternalServerError).
+					WithPayload(buildInternalErrorPayload(messages.ErrQueryOrderHistory, mapErr.Error()))
 			}
 			result[index] = tmpStatus
 		}
@@ -157,16 +160,16 @@ func (h *OrderStatus) AddNewStatusToOrder(
 
 		newOrderStatus := params.Data.Status
 		if newOrderStatus == nil {
-			h.logger.Error("Status is empty")
+			h.logger.Error(messages.ErrOrderStatusEmpty)
 			return orders.NewAddNewOrderStatusDefault(http.StatusBadRequest).
-				WithPayload(buildStringPayload("Status is empty"))
+				WithPayload(buildBadRequestErrorPayload(messages.ErrOrderStatusEmpty, ""))
 		}
 
 		currentOrderStatus, err := orderStatusRepo.GetOrderCurrentStatus(ctx, int(*params.Data.OrderID))
 		if err != nil {
-			h.logger.Error("getting order current status failed", zap.Error(err))
+			h.logger.Error(messages.ErrGetOrderStatus, zap.Error(err))
 			return orders.NewAddNewOrderStatusDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Can't get order current status"))
+				WithPayload(buildInternalErrorPayload(messages.ErrGetOrderStatus, err.Error()))
 		}
 
 		canUserCancelOrder := canUserCancelOrder(userID, currentOrderStatus, *newOrderStatus)
@@ -175,7 +178,7 @@ func (h *OrderStatus) AddNewStatusToOrder(
 		if !canUserCancelOrder && !canRoleChangeStatus {
 			h.logger.Error("User does not have the right to create an order status", zap.Any("principal", principal))
 			return orders.NewAddNewOrderStatusDefault(http.StatusForbidden).
-				WithPayload(&models.Error{Data: &models.ErrorData{Message: "You don't have rights to add a new status"}})
+				WithPayload(buildForbiddenErrorPayload(messages.ErrCreateOrderStatusForbidden, ""))
 		}
 
 		orderID := currentOrderStatus.Edges.Order.ID
@@ -183,20 +186,20 @@ func (h *OrderStatus) AddNewStatusToOrder(
 		if err != nil {
 			h.logger.Error("GetEquipmentStatusByOrder error", zap.Error(err))
 			return orders.NewAddNewOrderStatusDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("can't get equipment status"))
+				WithPayload(buildInternalErrorPayload(messages.ErrGetEqStatus, err.Error()))
 		}
 
 		err = checkEqStatusRequirements(*newOrderStatus, h.logger, orderEquipmentStatuses)
 		if err != nil {
 			return orders.NewAddNewOrderStatusDefault(http.StatusInternalServerError).
-				WithPayload(buildErrorPayload(err))
+				WithPayload(buildInternalErrorPayload(messages.ErrUpdateOrderStatus, err.Error()))
 		}
 
 		err = orderStatusRepo.UpdateStatus(ctx, userID, *params.Data)
 		if err != nil {
-			h.logger.Error("Update order status error", zap.Error(err))
+			h.logger.Error(messages.ErrUpdateOrderStatus, zap.Error(err))
 			return orders.NewAddNewOrderStatusDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Can't update status"))
+				WithPayload(buildInternalErrorPayload(messages.ErrUpdateOrderStatus, err.Error()))
 		}
 
 		switch *newOrderStatus {
@@ -207,9 +210,9 @@ func (h *OrderStatus) AddNewStatusToOrder(
 			}
 			err = UpdateEqStatuses(ctx, equipmentStatusRepo, orderEquipmentStatuses, model)
 			if err != nil {
-				h.logger.Error("Update equipment status error", zap.Error(err))
+				h.logger.Error(messages.ErrUpdateEqStatus, zap.Error(err))
 				return orders.NewAddNewOrderStatusDefault(http.StatusInternalServerError).
-					WithPayload(buildStringPayload("Can't update equipment status"))
+					WithPayload(buildInternalErrorPayload(messages.ErrUpdateEqStatus, err.Error()))
 			}
 
 		case domain.OrderStatusInProgress:
@@ -219,9 +222,9 @@ func (h *OrderStatus) AddNewStatusToOrder(
 			}
 			err = UpdateEqStatuses(ctx, equipmentStatusRepo, orderEquipmentStatuses, model)
 			if err != nil {
-				h.logger.Error("Update equipment status error", zap.Error(err))
+				h.logger.Error(messages.ErrUpdateEqStatus, zap.Error(err))
 				return orders.NewAddNewOrderStatusDefault(http.StatusInternalServerError).
-					WithPayload(buildStringPayload("Can't update equipment status"))
+					WithPayload(buildInternalErrorPayload(messages.ErrUpdateEqStatus, err.Error()))
 			}
 
 		case domain.OrderStatusClosed:
@@ -254,13 +257,13 @@ func (h *OrderStatus) AddNewStatusToOrder(
 
 			err = UpdateEqStatuses(ctx, equipmentStatusRepo, orderEquipmentStatuses, model)
 			if err != nil {
-				h.logger.Error("Update equipment status error", zap.Error(err))
+				h.logger.Error(messages.ErrUpdateEqStatus, zap.Error(err))
 				return orders.NewAddNewOrderStatusDefault(http.StatusInternalServerError).
-					WithPayload(buildStringPayload("Can't update equipment status"))
+					WithPayload(buildInternalErrorPayload(messages.ErrUpdateEqStatus, err.Error()))
 			}
 		}
 
-		return orders.NewAddNewOrderStatusOK().WithPayload("all ok")
+		return orders.NewAddNewOrderStatusOK().WithPayload(messages.MsgAllOk)
 	}
 }
 
@@ -276,7 +279,7 @@ func (h *OrderStatus) GetOrdersByStatus(repository domain.OrderRepositoryWithFil
 		if err != nil {
 			h.logger.Error("GetOrdersByStatus error", zap.Error(err))
 			return orders.NewGetOrdersByStatusDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload(fmt.Sprintf("Can't get total count of orders by status. error: %s", err.Error())))
+				WithPayload(buildInternalErrorPayload(messages.ErrQueryTotalOrdersByStatus, err.Error()))
 		}
 
 		var ordersByStatus []*ent.Order
@@ -285,7 +288,7 @@ func (h *OrderStatus) GetOrdersByStatus(repository domain.OrderRepositoryWithFil
 			if err != nil {
 				h.logger.Error("GetOrdersByStatus error", zap.Error(err))
 				return orders.NewGetOrdersByStatusDefault(http.StatusInternalServerError).
-					WithPayload(buildStringPayload(fmt.Sprintf("Can't get orders by status. error: %s", err.Error())))
+					WithPayload(buildInternalErrorPayload(messages.ErrQueryOrdersByStatus, err.Error()))
 			}
 		}
 		ordersResult := make([]*models.UserOrder, len(ordersByStatus))
@@ -294,7 +297,7 @@ func (h *OrderStatus) GetOrdersByStatus(repository domain.OrderRepositoryWithFil
 			if errMap != nil {
 				h.logger.Error("GetOrdersByStatus error", zap.Error(errMap))
 				return orders.NewGetOrdersByStatusDefault(http.StatusInternalServerError).
-					WithPayload(&models.Error{Data: &models.ErrorData{Message: "Can't map order"}})
+					WithPayload(buildInternalErrorPayload(messages.ErrMapOrder, errMap.Error()))
 			}
 			ordersResult[index] = tmpOrder
 		}
@@ -321,7 +324,7 @@ func (h *OrderStatus) GetOrdersByPeriodAndStatus(repository domain.OrderReposito
 		if err != nil {
 			h.logger.Error("GetOrdersByPeriodAndStatus error", zap.Error(err))
 			return orders.NewGetOrdersByDateAndStatusDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Can't get total amount of orders by period and status"))
+				WithPayload(buildInternalErrorPayload(messages.ErrQueryTotalOrdersByPeriodAndStatus, err.Error()))
 		}
 
 		var ordersByPeriodAndStatus []*ent.Order
@@ -332,7 +335,7 @@ func (h *OrderStatus) GetOrdersByPeriodAndStatus(repository domain.OrderReposito
 			if err != nil {
 				h.logger.Error("GetOrdersByPeriodAndStatus error", zap.Error(err))
 				return orders.NewGetOrdersByDateAndStatusDefault(http.StatusInternalServerError).
-					WithPayload(buildStringPayload("Can't get orders by period and status"))
+					WithPayload(buildInternalErrorPayload(messages.ErrQueryOrdersByPeriodAndStatus, err.Error()))
 			}
 		}
 		ordersResult := make([]*models.UserOrder, len(ordersByPeriodAndStatus))
@@ -341,7 +344,7 @@ func (h *OrderStatus) GetOrdersByPeriodAndStatus(repository domain.OrderReposito
 			if errMap != nil {
 				h.logger.Error("GetOrdersByPeriodAndStatus error", zap.Error(errMap))
 				return orders.NewGetOrdersByDateAndStatusDefault(http.StatusInternalServerError).
-					WithPayload(buildStringPayload("Can't map order"))
+					WithPayload(buildInternalErrorPayload(messages.ErrMapOrder, errMap.Error()))
 			}
 			ordersResult[index] = tmpOrder
 		}
@@ -364,15 +367,15 @@ func (h *OrderStatus) GetAllStatusNames(repository domain.OrderStatusNameReposit
 		if err != nil {
 			h.logger.Error("GetAllStatusNames error", zap.Error(err))
 			return orders.NewGetAllStatusNamesDefault(http.StatusInternalServerError).
-				WithPayload(&models.Error{Data: &models.ErrorData{Message: "Can't get all status names"}})
+				WithPayload(buildInternalErrorPayload(messages.ErrQueryStatusNames, err.Error()))
 		}
 		statusNamesResult := make([]*models.OrderStatusName, len(statusNames))
 		for index, statusName := range statusNames {
 			tmpStatusName, errMap := MapOrderStatusName(statusName)
 			if errMap != nil {
-				h.logger.Error("Cant map ent order status name to model order status name", zap.Error(errMap))
+				h.logger.Error(messages.ErrMapOrderStatus, zap.Error(errMap))
 				return orders.NewGetAllStatusNamesDefault(http.StatusInternalServerError).
-					WithPayload(&models.Error{Data: &models.ErrorData{Message: "Can't map order status name"}})
+					WithPayload(buildInternalErrorPayload(messages.ErrMapOrderStatus, errMap.Error()))
 			}
 			statusNamesResult[index] = tmpStatusName
 		}
diff --git a/internal/handlers/order_status_test.go b/internal/handlers/order_status_test.go
index da9963e2..1307b9d4 100644
--- a/internal/handlers/order_status_test.go
+++ b/internal/handlers/order_status_test.go
@@ -1049,12 +1049,13 @@ func (s *OrderStatusTestSuite) TestOrderStatus_AddNewStatusToOrder_ApprovedToPre
 	responseRecorder := httptest.NewRecorder()
 	producer := runtime.JSONProducer()
 	resp.WriteResponse(responseRecorder, producer)
-	response := models.Error{}
+	response := models.SwaggerError{}
 	err := json.Unmarshal(responseRecorder.Body.Bytes(), &response)
 	require.NoError(t, err)
 	require.NotEmpty(t, response)
-	require.NotEmpty(t, response.Data)
-	require.Contains(t, response.Data.Message, "equipment IDs don't have correspondent status: [1]")
+	require.NotEmpty(t, response.Message)
+	require.Contains(t, *response.Message, "can't update status")
+	require.Contains(t, response.Details, "equipment IDs don't have correspondent status: [1]")
 	require.Equal(t, http.StatusInternalServerError, responseRecorder.Code)
 	s.orderStatusRepository.AssertExpectations(t)
 }
diff --git a/internal/handlers/order_test.go b/internal/handlers/order_test.go
index ecb25fc4..685bb720 100644
--- a/internal/handlers/order_test.go
+++ b/internal/handlers/order_test.go
@@ -3,7 +3,6 @@ package handlers
 import (
 	"encoding/json"
 	"errors"
-	"fmt"
 	"math"
 	"net/http"
 	"net/http/httptest"
@@ -151,14 +150,14 @@ func (s *orderTestSuite) TestOrder_ListUserOrders_WrongStatus() {
 	producer := runtime.JSONProducer()
 	resp.WriteResponse(responseRecorder, producer)
 
-	var response models.Error
+	var response models.SwaggerError
 	err := json.Unmarshal(responseRecorder.Body.Bytes(), &response)
 	if err != nil {
 		t.Fatal(err)
 	}
 
 	require.Equal(t, http.StatusBadRequest, responseRecorder.Code)
-	require.Equal(t, fmt.Sprintf("Invalid order status '%v'", st), response.Data.Message)
+	require.Equal(t, "can't get orders", *response.Message)
 }
 
 func (s *orderTestSuite) TestOrder_ListUserOrders_MapErr() {
@@ -832,7 +831,7 @@ func (s *orderTestSuite) TestOrder_CreateOrder_NoAvailableEquipments() {
 	responseRecorder := httptest.NewRecorder()
 	producer := runtime.JSONProducer()
 	resp.WriteResponse(responseRecorder, producer)
-	require.Equal(t, http.StatusInternalServerError, responseRecorder.Code)
+	require.Equal(t, http.StatusConflict, responseRecorder.Code)
 	responseOrder := models.Order{}
 	err := json.Unmarshal(responseRecorder.Body.Bytes(), &responseOrder)
 	if err != nil {
diff --git a/internal/handlers/password_reset.go b/internal/handlers/password_reset.go
index 727cd767..6088f195 100644
--- a/internal/handlers/password_reset.go
+++ b/internal/handlers/password_reset.go
@@ -9,6 +9,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/password_reset"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
 )
 
@@ -37,19 +38,17 @@ func (c passwordResetHandler) SendLinkByLoginFunc() password_reset.SendLinkByLog
 		login := *s.Login.Data.Login
 		if login == "" {
 			c.logger.Warn("Login is empty")
-			return password_reset.NewSendLinkByLoginDefault(http.StatusBadRequest).WithPayload(
-				&models.Error{
-					Data: &models.ErrorData{
-						Message: "Login is required",
-					},
-				})
+			return password_reset.NewSendLinkByLoginDefault(http.StatusBadRequest).
+				WithPayload(buildBadRequestErrorPayload(messages.ErrLoginRequired, ""))
 		}
 		err := c.passwordReset.SendResetPasswordLink(ctx, login)
 		if err != nil {
 			c.logger.Error("Error while sending reset password link", zap.Error(err))
-			return password_reset.NewSendLinkByLoginOK().WithPayload("Check your email for a reset link")
+			return password_reset.NewSendLinkByLoginOK().WithPayload(
+				models.PasswordResetResponse(messages.MsgPasswordResetSuccesful))
 		}
-		return password_reset.NewSendLinkByLoginOK().WithPayload("Check your email for a reset link")
+		return password_reset.NewSendLinkByLoginOK().WithPayload(
+			models.PasswordResetResponse(messages.MsgPasswordResetSuccesful))
 	}
 }
 
diff --git a/internal/handlers/pet_kind.go b/internal/handlers/pet_kind.go
index ada30290..5e7c15d9 100644
--- a/internal/handlers/pet_kind.go
+++ b/internal/handlers/pet_kind.go
@@ -9,6 +9,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/pet_kind"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/repositories"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
 )
@@ -40,14 +41,14 @@ func (pk PetKind) CreatePetKindFunc(repository domain.PetKindRepository) pet_kin
 		ctx := p.HTTPRequest.Context()
 		petKind, err := repository.Create(ctx, *p.NewPetKind)
 		if err != nil {
-			pk.logger.Error("Error while creating pet kind", zap.Error(err))
+			pk.logger.Error(messages.ErrCreatePetKind, zap.Error(err))
 			return pet_kind.NewCreateNewPetKindDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while creating pet kind"))
+				WithPayload(buildInternalErrorPayload(messages.ErrCreatePetKind, err.Error()))
 		}
 		if petKind == nil {
 			pk.logger.Error("Pet kind is nil")
 			return pet_kind.NewCreateNewPetKindDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while creating pet kind"))
+				WithPayload(buildInternalErrorPayload(messages.ErrCreatePetKind, ""))
 		}
 		id := int64(petKind.ID)
 		return pet_kind.NewCreateNewPetKindCreated().WithPayload(&models.PetKindResponse{
@@ -63,13 +64,13 @@ func (pk PetKind) GetAllPetKindFunc(repository domain.PetKindRepository) pet_kin
 		ctx := p.HTTPRequest.Context()
 		petKinds, err := repository.GetAll(ctx)
 		if err != nil {
-			pk.logger.Error("Error while getting pet kind", zap.Error(err))
+			pk.logger.Error(messages.ErrGetPetKind, zap.Error(err))
 			return pet_kind.NewCreateNewPetKindDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while getting pet kind"))
+				WithPayload(buildInternalErrorPayload(messages.ErrGetPetKind, err.Error()))
 		}
 		if len(petKinds) == 0 {
 			return pet_kind.NewCreateNewPetKindDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("No pet kind found"))
+				WithPayload(buildInternalErrorPayload(messages.ErrPetKindNotFound, ""))
 		}
 		listOfPetKind := models.ListOfPetKinds{}
 		for _, v := range petKinds {
@@ -86,13 +87,13 @@ func (pk PetKind) GetPetKindsByID(repo domain.PetKindRepository) pet_kind.GetPet
 		ctx := p.HTTPRequest.Context()
 		petKind, err := repo.GetByID(ctx, int(p.PetKindID))
 		if err != nil {
-			pk.logger.Error("Error while getting pet kind by id", zap.Error(err))
+			pk.logger.Error(messages.ErrGetPetKind, zap.Error(err))
 			return pet_kind.NewCreateNewPetKindDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while getting pet kind"))
+				WithPayload(buildInternalErrorPayload(messages.ErrGetPetKind, err.Error()))
 		}
 		if petKind == nil {
 			return pet_kind.NewCreateNewPetKindDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while getting pet kind"))
+				WithPayload(buildInternalErrorPayload(messages.ErrGetPetKind, ""))
 		}
 		id := int64(petKind.ID)
 		return pet_kind.NewGetPetKindOK().WithPayload(&models.PetKindResponse{ID: &id, Name: &petKind.Name})
@@ -104,11 +105,11 @@ func (pk PetKind) DeletePetKindByID(repo domain.PetKindRepository) pet_kind.Dele
 		ctx := p.HTTPRequest.Context()
 		err := repo.Delete(ctx, int(p.PetKindID))
 		if err != nil {
-			pk.logger.Error("Error while deleting pet kind by id", zap.Error(err))
+			pk.logger.Error(messages.ErrDeletePetKind, zap.Error(err))
 			return pet_kind.NewCreateNewPetKindDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while deleting pet kind"))
+				WithPayload(buildInternalErrorPayload(messages.ErrDeletePetKind, err.Error()))
 		}
-		return pet_kind.NewDeletePetKindOK().WithPayload("Pet kind deleted")
+		return pet_kind.NewDeletePetKindOK().WithPayload(messages.MsgPetKindDeleted)
 	}
 }
 
@@ -117,14 +118,14 @@ func (pk PetKind) UpdatePetKindByID(repo domain.PetKindRepository) pet_kind.Edit
 		ctx := p.HTTPRequest.Context()
 		petSize, err := repo.Update(ctx, int(p.PetKindID), p.EditPetKind)
 		if err != nil {
-			pk.logger.Error("Error while updating pet kind by id", zap.Error(err))
+			pk.logger.Error(messages.ErrUpdatePetKind, zap.Error(err))
 			return pet_kind.NewCreateNewPetKindDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while updating pet kind"))
+				WithPayload(buildInternalErrorPayload(messages.ErrUpdatePetKind, err.Error()))
 		}
 		if petSize == nil {
-			pk.logger.Error("Error while updating pet kind by id", zap.Error(err))
+			pk.logger.Error(messages.ErrUpdatePetKind, zap.Error(err))
 			return pet_kind.NewCreateNewPetKindDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while updating pet kind"))
+				WithPayload(buildInternalErrorPayload(messages.ErrUpdatePetKind, ""))
 		}
 
 		id := int64(petSize.ID)
diff --git a/internal/handlers/pet_size.go b/internal/handlers/pet_size.go
index 669b5773..234956d6 100644
--- a/internal/handlers/pet_size.go
+++ b/internal/handlers/pet_size.go
@@ -9,6 +9,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/pet_size"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/repositories"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
 )
@@ -39,43 +40,27 @@ func (ps PetSize) CreatePetSizeFunc(repository domain.PetSizeRepository) pet_siz
 		ctx := p.HTTPRequest.Context()
 		allPetSizes, err := repository.GetAll(ctx)
 		if err != nil {
-			ps.logger.Error("Error while getting pet size", zap.Error(err))
-			return pet_size.NewCreateNewPetSizeDefault(http.StatusInternalServerError).WithPayload(
-				&models.Error{
-					Data: &models.ErrorData{
-						Message: "Error while creating pet size",
-					},
-				})
+			ps.logger.Error(messages.ErrGetPetSize, zap.Error(err))
+			return pet_size.NewCreateNewPetSizeDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrCreatePetSize, err.Error()))
 		}
 		for _, petSize := range allPetSizes {
 			if *p.NewPetSize.Name == petSize.Name {
-				ps.logger.Error("Error while creating pet size", zap.Error(err))
-				return pet_size.NewCreateNewPetSizeDefault(http.StatusInternalServerError).WithPayload(
-					&models.Error{
-						Data: &models.ErrorData{
-							Message: "Error while creating pet size: the name already exist",
-						},
-					})
+				ps.logger.Error(messages.ErrCreatePetSize, zap.Error(err))
+				return pet_size.NewCreateNewPetSizeDefault(http.StatusInternalServerError).
+					WithPayload(buildInternalErrorPayload(messages.ErrPetSizeAlreadyExists, ""))
 			}
 		}
 		petSize, err := repository.Create(ctx, *p.NewPetSize)
 		if err != nil {
-			ps.logger.Error("Error while creating pet size", zap.Error(err))
-			return pet_size.NewCreateNewPetSizeDefault(http.StatusInternalServerError).WithPayload(
-				&models.Error{
-					Data: &models.ErrorData{
-						Message: "Error while creating pet size",
-					},
-				})
+			ps.logger.Error(messages.ErrCreatePetSize, zap.Error(err))
+			return pet_size.NewCreateNewPetSizeDefault(http.StatusInternalServerError).
+				WithPayload(buildBadRequestErrorPayload(messages.ErrCreatePetSize, err.Error()))
 		}
 		if petSize == nil {
 			ps.logger.Error("Pet size is nil")
-			return pet_size.NewCreateNewPetSizeDefault(http.StatusInternalServerError).WithPayload(
-				&models.Error{
-					Data: &models.ErrorData{
-						Message: "Error while creating pet size",
-					},
-				})
+			return pet_size.NewCreateNewPetSizeDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrCreatePetSize, ""))
 		}
 		id := int64(petSize.ID)
 		return pet_size.NewCreateNewPetSizeCreated().WithPayload(&models.PetSizeResponse{
@@ -93,21 +78,13 @@ func (ps PetSize) GetAllPetSizeFunc(repository domain.PetSizeRepository) pet_siz
 		ctx := p.HTTPRequest.Context()
 		petSizes, err := repository.GetAll(ctx)
 		if err != nil {
-			ps.logger.Error("Error while getting pet size", zap.Error(err))
-			return pet_size.NewGetAllPetSizeDefault(http.StatusInternalServerError).WithPayload(
-				&models.Error{
-					Data: &models.ErrorData{
-						Message: "Error while getting pet size",
-					},
-				})
+			ps.logger.Error(messages.ErrGetPetSize, zap.Error(err))
+			return pet_size.NewGetAllPetSizeDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrGetPetSize, ""))
 		}
 		if len(petSizes) == 0 {
-			return pet_size.NewGetAllPetSizeDefault(http.StatusInternalServerError).WithPayload(
-				&models.Error{
-					Data: &models.ErrorData{
-						Message: "No pet size found",
-					},
-				})
+			return pet_size.NewGetAllPetSizeDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrPetSizeNotFound, ""))
 		}
 		listOfPetSize := models.ListOfPetSizes{}
 		for _, v := range petSizes {
@@ -128,21 +105,13 @@ func (ps PetSize) GetPetSizeByID(repo domain.PetSizeRepository) pet_size.GetPetS
 		ctx := p.HTTPRequest.Context()
 		petSize, err := repo.GetByID(ctx, int(p.PetSizeID))
 		if err != nil {
-			ps.logger.Error("Error while getting pet size by id", zap.Error(err))
-			return pet_size.NewGetPetSizeDefault(http.StatusInternalServerError).WithPayload(
-				&models.Error{
-					Data: &models.ErrorData{
-						Message: "Error while getting pet size",
-					},
-				})
+			ps.logger.Error(messages.ErrGetPetSize, zap.Error(err))
+			return pet_size.NewGetPetSizeDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrGetPetSize, err.Error()))
 		}
 		if petSize == nil {
-			return pet_size.NewGetPetSizeDefault(http.StatusInternalServerError).WithPayload(
-				&models.Error{
-					Data: &models.ErrorData{
-						Message: "Error while getting pet size",
-					},
-				})
+			return pet_size.NewGetPetSizeDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrGetPetSize, ""))
 		}
 		id := int64(petSize.ID)
 		return pet_size.NewGetPetSizeOK().WithPayload(&models.PetSizeResponse{ID: &id, Name: &petSize.Name, Size: &petSize.Size})
@@ -154,15 +123,11 @@ func (ps PetSize) DeletePetSizeByID(repo domain.PetSizeRepository) pet_size.Dele
 		ctx := p.HTTPRequest.Context()
 		err := repo.Delete(ctx, int(p.PetSizeID))
 		if err != nil {
-			ps.logger.Error("Error while deleting pet size by id", zap.Error(err))
-			return pet_size.NewDeletePetSizeDefault(http.StatusInternalServerError).WithPayload(
-				&models.Error{
-					Data: &models.ErrorData{
-						Message: "Error while deleting pet size",
-					},
-				})
+			ps.logger.Error(messages.ErrDeletePetSize, zap.Error(err))
+			return pet_size.NewDeletePetSizeDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrDeletePetSize, err.Error()))
 		}
-		return pet_size.NewDeletePetSizeOK().WithPayload("Pet size deleted")
+		return pet_size.NewDeletePetSizeOK().WithPayload(messages.MsgPetSizeDeleted)
 	}
 }
 
@@ -171,22 +136,14 @@ func (ps PetSize) UpdatePetSizeByID(repo domain.PetSizeRepository) pet_size.Edit
 		ctx := p.HTTPRequest.Context()
 		petSize, err := repo.Update(ctx, int(p.PetSizeID), p.EditPetSize)
 		if err != nil {
-			ps.logger.Error("Error while updating pet size by id", zap.Error(err))
-			return pet_size.NewEditPetSizeDefault(http.StatusInternalServerError).WithPayload(
-				&models.Error{
-					Data: &models.ErrorData{
-						Message: "Error while updating pet size",
-					},
-				})
+			ps.logger.Error(messages.ErrUpdatePetSize, zap.Error(err))
+			return pet_size.NewEditPetSizeDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrUpdatePetSize, err.Error()))
 		}
 		if petSize == nil {
-			ps.logger.Error("Error while updating pet size by id", zap.Error(err))
-			return pet_size.NewEditPetSizeDefault(http.StatusInternalServerError).WithPayload(
-				&models.Error{
-					Data: &models.ErrorData{
-						Message: "Error while updating pet size",
-					},
-				})
+			ps.logger.Error(messages.ErrUpdatePetSize, zap.Error(err))
+			return pet_size.NewEditPetSizeDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrUpdatePetSize, ""))
 		}
 
 		id := int64(petSize.ID)
diff --git a/internal/handlers/photo.go b/internal/handlers/photo.go
index 626b6549..64f2536f 100644
--- a/internal/handlers/photo.go
+++ b/internal/handlers/photo.go
@@ -14,6 +14,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/photos"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/repositories"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/utils"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
@@ -47,32 +48,32 @@ func (p Photo) CreateNewPhotoFunc(repository domain.PhotoRepository) photos.Crea
 		if err != nil {
 			p.logger.Error("failed to read file", zap.Error(err))
 			return photos.NewCreateNewPhotoDefault(http.StatusInternalServerError).
-				WithPayload(buildErrorPayload(err))
+				WithPayload(buildInternalErrorPayload(messages.ErrCreatePhoto, err.Error()))
 		}
 		if err := s.File.Close(); err != nil {
 			p.logger.Error("Failed to close file", zap.Error(err))
 			return photos.NewCreateNewPhotoDefault(http.StatusInternalServerError).
-				WithPayload(buildErrorPayload(err))
+				WithPayload(buildInternalErrorPayload(messages.ErrCreatePhoto, err.Error()))
 		}
 		// check if file is not empty
 		if len(fileBytes) == 0 {
-			p.logger.Error("file is empty")
+			p.logger.Error(messages.ErrFileEmpty)
 			return photos.NewCreateNewPhotoDefault(http.StatusBadRequest).
-				WithPayload(buildStringPayload("File is empty"))
+				WithPayload(buildBadRequestErrorPayload(messages.ErrFileEmpty, ""))
 		}
 		// check if file is image jpg/jpeg
 		mimeType := http.DetectContentType(fileBytes)
 		if mimeType != "image/jpg" && mimeType != "image/jpeg" {
 			p.logger.Error(fmt.Sprintf("wrong file format: %s. file should be jpg or jpeg", mimeType))
 			return photos.NewCreateNewPhotoDefault(http.StatusBadRequest).
-				WithPayload(buildStringPayload("Wrong file format. File should be jpg or jpeg"))
+				WithPayload(buildBadRequestErrorPayload(messages.ErrWrongFormat, ""))
 		}
 
 		photoID, err := utils.GenerateFileName()
 		if err != nil {
 			p.logger.Error("failed to generate photo name", zap.Error(err))
 			return photos.NewCreateNewPhotoDefault(http.StatusInternalServerError).
-				WithPayload(buildErrorPayload(err))
+				WithPayload(buildInternalErrorPayload(messages.ErrCreatePhoto, err.Error()))
 		}
 
 		fileName := fmt.Sprintf("%s.jpg", photoID)
@@ -86,7 +87,7 @@ func (p Photo) CreateNewPhotoFunc(repository domain.PhotoRepository) photos.Crea
 		if err != nil {
 			p.logger.Error("failed to save photo to db", zap.Error(err))
 			return photos.NewCreateNewPhotoDefault(http.StatusInternalServerError).
-				WithPayload(buildErrorPayload(err))
+				WithPayload(buildInternalErrorPayload(messages.ErrCreatePhoto, err.Error()))
 		}
 		return photos.NewCreateNewPhotoCreated().WithPayload(&models.CreateNewPhotoResponse{
 			Data: &models.Photo{
@@ -103,7 +104,7 @@ func (p Photo) GetPhotoFunc(repository domain.PhotoRepository) photos.GetPhotoHa
 			ctx := s.HTTPRequest.Context()
 			photo, err := repository.PhotoByID(ctx, s.PhotoID)
 			if err != nil {
-				p.logger.Error("failed to get photo", zap.Error(err))
+				p.logger.Error(messages.ErrGetPhoto, zap.Error(err))
 				if err := writeErrorInResponse(w, err); err != nil {
 					p.logger.Error("failed to response to client", zap.Error(err))
 				}
@@ -126,7 +127,7 @@ func (p Photo) DownloadPhotoFunc(repository domain.PhotoRepository) photos.Downl
 			ctx := s.HTTPRequest.Context()
 			photo, err := repository.PhotoByID(ctx, s.PhotoID)
 			if err != nil {
-				p.logger.Error("failed to get photo", zap.Error(err))
+				p.logger.Error(messages.ErrGetPhoto, zap.Error(err))
 				if err := writeErrorInResponse(w, err); err != nil {
 					p.logger.Error("failed to response to client", zap.Error(err))
 				}
@@ -156,28 +157,28 @@ func (p Photo) DeletePhotoFunc(repository domain.PhotoRepository) photos.DeleteP
 		ctx := s.HTTPRequest.Context()
 		photo, err := repository.PhotoByID(ctx, s.PhotoID)
 		if err != nil {
-			p.logger.Error("failed to get photo", zap.Error(err))
+			p.logger.Error(messages.ErrGetPhoto, zap.Error(err))
 			return photos.NewDeletePhotoDefault(http.StatusInternalServerError).
-				WithPayload(buildErrorPayload(err))
+				WithPayload(buildInternalErrorPayload(messages.ErrDeletePhoto, err.Error()))
 		}
 
 		err = repository.DeletePhotoByID(ctx, photo.ID)
 		if err != nil {
 			p.logger.Error("delete photo failed", zap.Error(err))
 			return photos.NewDeletePhotoDefault(http.StatusInternalServerError).
-				WithPayload(buildErrorPayload(err))
+				WithPayload(buildInternalErrorPayload(messages.ErrDeletePhoto, err.Error()))
 		}
 		//err = fileManager.DeleteFile(photo.FileName)
 		//if err != nil {
 		//	p.logger.Error("failed to delete photo file", zap.Error(err))
 		//}
 
-		return photos.NewDeletePhotoOK().WithPayload("Photo deleted")
+		return photos.NewDeletePhotoOK().WithPayload(messages.MsgPhotoDeleted)
 	}
 }
 
 func writeErrorInResponse(w http.ResponseWriter, err error) error {
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(http.StatusInternalServerError)
-	return json.NewEncoder(w).Encode(buildErrorPayload(err))
+	return json.NewEncoder(w).Encode(buildInternalErrorPayload(messages.ErrGetPhoto, err.Error()))
 }
diff --git a/internal/handlers/photo_test.go b/internal/handlers/photo_test.go
index 5883ab0c..5bb49a21 100644
--- a/internal/handlers/photo_test.go
+++ b/internal/handlers/photo_test.go
@@ -91,14 +91,14 @@ func (s *PhotoTestSuite) TestPhoto_CreatePhoto_EmptyFile() {
 	resp.WriteResponse(responseRecorder, producer)
 	require.Equal(t, http.StatusBadRequest, responseRecorder.Code)
 
-	response := models.Error{}
+	response := models.SwaggerError{}
 	err = json.Unmarshal(responseRecorder.Body.Bytes(), &response)
 	if err != nil {
 		t.Fatal(err)
 	}
 	require.NotEmpty(t, response)
-	require.NotEmpty(t, response.Data)
-	require.Equal(t, "File is empty", response.Data.Message)
+	require.NotEmpty(t, response.Message)
+	require.Equal(t, "File is empty", *response.Message)
 
 	s.repository.AssertExpectations(t)
 }
@@ -134,14 +134,14 @@ func (s *PhotoTestSuite) TestPhoto_CreatePhoto_WrongMimeType() {
 	resp.WriteResponse(responseRecorder, producer)
 	require.Equal(t, http.StatusBadRequest, responseRecorder.Code)
 
-	response := models.Error{}
+	response := models.SwaggerError{}
 	err = json.Unmarshal(responseRecorder.Body.Bytes(), &response)
 	if err != nil {
 		t.Fatal(err)
 	}
 	require.NotEmpty(t, response)
-	require.NotEmpty(t, response.Data)
-	require.Containsf(t, response.Data.Message, "Wrong file format", "returned wrong error")
+	require.NotEmpty(t, response.Message)
+	require.Containsf(t, *response.Message, "Wrong file format", "returned wrong error")
 
 	s.repository.AssertExpectations(t)
 }
@@ -257,14 +257,14 @@ func (s *PhotoTestSuite) TestPhoto_GetPhoto_RepoErr() {
 	require.Equal(t, http.StatusInternalServerError, responseRecorder.Code)
 	require.Equal(t, "application/json", responseRecorder.Header().Get("Content-Type"))
 
-	response := models.Error{}
+	response := models.SwaggerError{}
 	err := json.Unmarshal(responseRecorder.Body.Bytes(), &response)
 	if err != nil {
 		t.Fatal(err)
 	}
 	require.NotEmpty(t, response)
-	require.NotEmpty(t, response.Data)
-	require.Equal(t, errorToReturn.Error(), response.Data.Message)
+	require.NotEmpty(t, response.Message)
+	require.Contains(t, errorToReturn.Error(), response.Details)
 
 	s.repository.AssertExpectations(t)
 }
@@ -315,7 +315,7 @@ func (s *PhotoTestSuite) TestPhoto_DeletePhoto_NotExists() {
 		PhotoID:     id,
 	}
 
-	errorToReturn := errors.New("not found")
+	errorToReturn := errors.New("failed to delete photo")
 	s.repository.On("PhotoByID", ctx, data.PhotoID).Return(nil, errorToReturn)
 
 	handlerFunc := s.handler.DeletePhotoFunc(s.repository)
@@ -327,14 +327,14 @@ func (s *PhotoTestSuite) TestPhoto_DeletePhoto_NotExists() {
 	resp.WriteResponse(responseRecorder, producer)
 	require.Equal(t, http.StatusInternalServerError, responseRecorder.Code)
 
-	response := models.Error{}
+	response := models.SwaggerError{}
 	err := json.Unmarshal(responseRecorder.Body.Bytes(), &response)
 	if err != nil {
 		t.Fatal(err)
 	}
 	require.NotEmpty(t, response)
-	require.NotEmpty(t, response.Data)
-	require.Equal(t, errorToReturn.Error(), response.Data.Message)
+	require.NotEmpty(t, response.Message)
+	require.Equal(t, errorToReturn.Error(), *response.Message)
 
 	s.repository.AssertExpectations(t)
 }
diff --git a/internal/handlers/registration_confirm.go b/internal/handlers/registration_confirm.go
index 24bac781..c5c01b54 100644
--- a/internal/handlers/registration_confirm.go
+++ b/internal/handlers/registration_confirm.go
@@ -6,8 +6,10 @@ import (
 	"github.com/go-openapi/runtime/middleware"
 	"go.uber.org/zap"
 
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/registration_confirm"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/services"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
 )
@@ -38,7 +40,7 @@ func (rc registrationConfirmHandler) SendRegistrationConfirmLinkByLoginFunc() re
 		if login == "" {
 			rc.logger.Warn("Login is empty")
 			return registration_confirm.NewSendRegistrationConfirmLinkByLoginDefault(http.StatusBadRequest).
-				WithPayload(buildStringPayload("Login is required"))
+				WithPayload(buildBadRequestErrorPayload(messages.ErrLoginRequired, ""))
 		}
 		err := rc.regConfirm.SendConfirmationLink(ctx, login)
 		if err != nil {
@@ -46,19 +48,21 @@ func (rc registrationConfirmHandler) SendRegistrationConfirmLinkByLoginFunc() re
 			switch err {
 			case services.ErrRegistrationAlreadyConfirmed:
 				return registration_confirm.NewSendRegistrationConfirmLinkByLoginDefault(http.StatusInternalServerError).
-					WithPayload(buildStringPayload("Registration is already confirmed."))
+					WithPayload(buildInternalErrorPayload(messages.ErrRegistrationAlreadyConfirmed, ""))
 			case services.ErrUserNotFound:
 				return registration_confirm.NewSendRegistrationConfirmLinkByLoginDefault(http.StatusInternalServerError).
-					WithPayload(buildStringPayload("Can't find this user, registration confirmation link wasn't send"))
+					WithPayload(buildInternalErrorPayload(messages.ErrRegistrationCannotFindUser, ""))
 			default:
 				return registration_confirm.NewSendRegistrationConfirmLinkByLoginDefault(http.StatusInternalServerError).
-					WithPayload(buildStringPayload("Can't send registration confirmation link. Please try again later"))
+					WithPayload(buildInternalErrorPayload(messages.ErrRegistrationCannotSend, ""))
 			}
 		}
 		if !rc.regConfirm.IsSendRequired() {
-			return registration_confirm.NewSendRegistrationConfirmLinkByLoginOK().WithPayload("Confirmation link was not sent to email, sending parameter was set to false and not required")
+			return registration_confirm.NewSendRegistrationConfirmLinkByLoginOK().WithPayload(
+				models.RegistrationConfirmResponse(messages.MsgConfirmationNotRequired))
 		}
-		return registration_confirm.NewSendRegistrationConfirmLinkByLoginOK().WithPayload("Confirmation link was sent")
+		return registration_confirm.NewSendRegistrationConfirmLinkByLoginOK().WithPayload(
+			models.RegistrationConfirmResponse(messages.MsgConfirmationSent))
 	}
 }
 
@@ -70,8 +74,9 @@ func (rc registrationConfirmHandler) VerifyRegistrationConfirmTokenFunc() regist
 		if err != nil {
 			rc.logger.Error("Failed to verify confirmation token", zap.Error(err))
 			return registration_confirm.NewVerifyRegistrationConfirmTokenDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Failed to verify confirmation token. Please try again later"))
+				WithPayload(buildInternalErrorPayload(messages.ErrFailedToConfirm, ""))
 		}
-		return registration_confirm.NewVerifyRegistrationConfirmTokenOK().WithPayload("You have successfully confirmed registration")
+		return registration_confirm.NewVerifyRegistrationConfirmTokenOK().WithPayload(
+			models.RegistrationConfirmResponse(messages.MsgRegistrationConfirmed))
 	}
 }
diff --git a/internal/handlers/role.go b/internal/handlers/role.go
index 74510d0b..235c7d3c 100644
--- a/internal/handlers/role.go
+++ b/internal/handlers/role.go
@@ -9,6 +9,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/roles"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/repositories"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
 )
@@ -35,9 +36,9 @@ func (r Role) GetRolesFunc(repository domain.RoleRepository) roles.GetRolesHandl
 		ctx := s.HTTPRequest.Context()
 		e, err := repository.GetRoles(ctx)
 		if err != nil {
-			r.logger.Error("query orders failed")
+			r.logger.Error(messages.ErrQueryRoles)
 			return roles.NewGetRolesDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("cant get all roles"))
+				WithPayload(buildInternalErrorPayload(messages.ErrQueryRoles, ""))
 		}
 		listRoles := models.ListRoles{}
 		for _, element := range e {
diff --git a/internal/handlers/subcategory.go b/internal/handlers/subcategory.go
index 558d1c8c..510c921f 100644
--- a/internal/handlers/subcategory.go
+++ b/internal/handlers/subcategory.go
@@ -11,6 +11,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/subcategories"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/repositories"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
 )
@@ -42,15 +43,15 @@ func (s *Subcategory) CreateNewSubcategoryFunc(repository domain.SubcategoryRepo
 		categoryID := int(p.CategoryID)
 		createdSubcategory, err := repository.CreateSubcategory(ctx, categoryID, *p.NewSubcategory)
 		if err != nil {
-			s.logger.Error("failed to create new subcategory", zap.Error(err))
+			s.logger.Error(messages.ErrCreateSubcategory, zap.Error(err))
 			return subcategories.NewCreateNewSubcategoryDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("failed to create new subcategory"))
+				WithPayload(buildInternalErrorPayload(messages.ErrCreateSubcategory, err.Error()))
 		}
 		result, err := mapSubcategory(createdSubcategory)
 		if err != nil {
-			s.logger.Error("failed to map new subcategory", zap.Error(err))
+			s.logger.Error(messages.ErrMapSubcategory, zap.Error(err))
 			return subcategories.NewCreateNewSubcategoryDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("failed to map new subcategory"))
+				WithPayload(buildInternalErrorPayload(messages.ErrMapSubcategory, err.Error()))
 		}
 		return subcategories.NewCreateNewSubcategoryCreated().WithPayload(&models.SubcategoryResponse{
 			Data: result,
@@ -64,17 +65,17 @@ func (s *Subcategory) ListSubcategoriesFunc(repository domain.SubcategoryReposit
 		categoryID := int(p.CategoryID)
 		subcategoriesList, err := repository.ListSubcategories(ctx, categoryID)
 		if err != nil {
-			s.logger.Error("failed to list subcategories by category id", zap.Error(err))
+			s.logger.Error(messages.ErrQuerySCatByCategory, zap.Error(err))
 			return subcategories.NewListSubcategoriesByCategoryIDDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("failed to list subcategories by category id"))
+				WithPayload(buildInternalErrorPayload(messages.ErrQuerySCatByCategory, err.Error()))
 		}
 		mappedSubcategories := make([]*models.Subcategory, len(subcategoriesList))
 		for i, v := range subcategoriesList {
 			mappedSubcategory, err := mapSubcategory(v)
 			if err != nil {
-				s.logger.Error("failed to map subcategories by category id", zap.Error(err))
+				s.logger.Error(messages.ErrMapSubcategory, zap.Error(err))
 				return subcategories.NewListSubcategoriesByCategoryIDDefault(http.StatusInternalServerError).
-					WithPayload(buildStringPayload("failed to map subcategories by category id"))
+					WithPayload(buildInternalErrorPayload(messages.ErrMapSubcategory, err.Error()))
 			}
 			mappedSubcategories[i] = mappedSubcategory
 		}
@@ -87,15 +88,15 @@ func (s *Subcategory) GetSubcategoryByIDFunc(repository domain.SubcategoryReposi
 		ctx := p.HTTPRequest.Context()
 		subcategory, err := repository.SubcategoryByID(ctx, int(p.SubcategoryID))
 		if err != nil {
-			s.logger.Error("failed to get subcategory", zap.Error(err))
+			s.logger.Error(messages.ErrGetSubcategory, zap.Error(err))
 			return subcategories.NewGetSubcategoryByIDDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("failed to get subcategory"))
+				WithPayload(buildInternalErrorPayload(messages.ErrGetSubcategory, err.Error()))
 		}
 		result, err := mapSubcategory(subcategory)
 		if err != nil {
-			s.logger.Error("failed to map subcategory", zap.Error(err))
+			s.logger.Error(messages.ErrMapSubcategory, zap.Error(err))
 			return subcategories.NewGetSubcategoryByIDDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("failed to map subcategory"))
+				WithPayload(buildInternalErrorPayload(messages.ErrMapSubcategory, err.Error()))
 		}
 		return subcategories.NewGetSubcategoryByIDOK().
 			WithPayload(&models.SubcategoryResponse{Data: result})
@@ -107,12 +108,12 @@ func (s *Subcategory) DeleteSubcategoryFunc(repository domain.SubcategoryReposit
 		ctx := p.HTTPRequest.Context()
 		err := repository.DeleteSubcategoryByID(ctx, int(p.SubcategoryID))
 		if err != nil {
-			s.logger.Error("failed to delete subcategory", zap.Error(err))
+			s.logger.Error(messages.ErrDeleteSubcategory, zap.Error(err))
 			return subcategories.NewDeleteSubcategoryDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("failed to delete subcategory"))
+				WithPayload(buildInternalErrorPayload(messages.ErrDeleteSubcategory, err.Error()))
 		}
 		return subcategories.NewDeleteSubcategoryOK().
-			WithPayload("subcategory deleted")
+			WithPayload(messages.MsgSubcategoryDeleted)
 	}
 }
 
@@ -121,15 +122,15 @@ func (s *Subcategory) UpdateSubcategoryFunc(repository domain.SubcategoryReposit
 		ctx := p.HTTPRequest.Context()
 		updateSubcategory, err := repository.UpdateSubcategory(ctx, int(p.SubcategoryID), *p.UpdateSubcategory)
 		if err != nil {
-			s.logger.Error("failed to update subcategory", zap.Error(err))
+			s.logger.Error(messages.ErrUpdateSubcategory, zap.Error(err))
 			return subcategories.NewUpdateSubcategoryDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("failed to update subcategory"))
+				WithPayload(buildInternalErrorPayload(messages.ErrUpdateSubcategory, err.Error()))
 		}
 		result, err := mapSubcategory(updateSubcategory)
 		if err != nil {
-			s.logger.Error("failed to map subcategory", zap.Error(err))
+			s.logger.Error(messages.ErrMapSubcategory, zap.Error(err))
 			return subcategories.NewUpdateSubcategoryDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("failed to map subcategory"))
+				WithPayload(buildInternalErrorPayload(messages.ErrMapSubcategory, err.Error()))
 		}
 		return subcategories.NewUpdateSubcategoryOK().WithPayload(&models.SubcategoryResponse{
 			Data: result,
diff --git a/internal/handlers/user.go b/internal/handlers/user.go
index cdc09642..b00d56bb 100644
--- a/internal/handlers/user.go
+++ b/internal/handlers/user.go
@@ -15,6 +15,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/restapi/operations/users"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/repositories"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/utils"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
@@ -62,7 +63,7 @@ func (c User) LoginUserFunc(service domain.TokenManager) users.LoginHandlerFunc
 			if isInternalErr {
 				return users.NewLoginDefault(http.StatusInternalServerError)
 			}
-			return users.NewLoginUnauthorized().WithPayload("Invalid login or password")
+			return users.NewLoginUnauthorized().WithPayload(messages.ErrInvalidLoginOrPass)
 		}
 
 		return users.NewLoginOK().WithPayload(&models.TokenPair{
@@ -83,7 +84,7 @@ func (c User) LogoutUserFunc(tokenManager domain.TokenManager) users.LogoutHandl
 		if err != nil {
 			return users.NewLogoutDefault(http.StatusInternalServerError)
 		}
-		return users.NewLogoutOK().WithPayload("Successfully logged out")
+		return users.NewLogoutOK().WithPayload(messages.MsgLogoutSuccessful)
 	}
 }
 
@@ -93,11 +94,11 @@ func (c User) PostUserFunc(repository domain.UserRepository, regConfirmService d
 		createdUser, err := repository.CreateUser(ctx, p.Data)
 		if err != nil {
 			if ent.IsConstraintError(err) {
-				return users.NewPostUserDefault(http.StatusExpectationFailed).WithPayload(
-					buildErrorPayload(errors.New("login is already used")),
-				)
+				return users.NewPostUserDefault(http.StatusExpectationFailed).
+					WithPayload(buildExFailedErrorPayload(messages.ErrLoginInUse, ""))
 			}
-			return users.NewPostUserDefault(http.StatusInternalServerError).WithPayload(buildErrorPayload(err))
+			return users.NewPostUserDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrCreateUser, err.Error()))
 		}
 
 		id := int64(createdUser.ID)
@@ -122,14 +123,14 @@ func (c User) Refresh(manager domain.TokenManager) users.RefreshHandlerFunc {
 		refreshToken := *p.RefreshToken.RefreshToken
 		newAccess, NewRefresh, isValid, err := manager.RefreshToken(ctx, refreshToken)
 		if isValid {
-			c.logger.Info("token invalid", zap.String("token", refreshToken))
+			c.logger.Info(messages.ErrInvalidToken, zap.String("token", refreshToken))
 			return users.NewRefreshDefault(http.StatusBadRequest).
-				WithPayload(buildStringPayload("token invalid"))
+				WithPayload(buildBadRequestErrorPayload(messages.ErrInvalidToken, ""))
 		}
 		if err != nil {
-			c.logger.Error("Error while refreshing token", zap.Error(err))
+			c.logger.Error(messages.ErrTokenRefresh, zap.Error(err))
 			return users.NewRefreshDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while refreshing token"))
+				WithPayload(buildInternalErrorPayload(messages.ErrTokenRefresh, err.Error()))
 		}
 		return users.NewRefreshOK().WithPayload(&models.TokenPair{
 			AccessToken:  &newAccess,
@@ -145,17 +146,16 @@ func (c User) GetUserFunc(repository domain.UserRepository) users.GetCurrentUser
 
 		user, err := repository.GetUserByID(ctx, userID)
 		if err != nil {
-			c.logger.Error("get user by id error", zap.Error(err))
-			return users.NewGetCurrentUserDefault(http.StatusInternalServerError).WithPayload(&models.Error{Data: &models.ErrorData{
-				Message: "cant find user by id",
-			}})
+			c.logger.Error(messages.ErrUserNotFound, zap.Error(err))
+			return users.NewGetCurrentUserDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrUserNotFound, ""))
 		}
 
 		result, err := mapUserInfo(user)
 		if err != nil {
-			c.logger.Error("map user error", zap.Error(err))
+			c.logger.Error(messages.ErrMapUser, zap.Error(err))
 			return users.NewGetCurrentUserDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("map user error"))
+				WithPayload(buildInternalErrorPayload(messages.ErrMapUser, err.Error()))
 		}
 
 		return users.NewGetCurrentUserOK().WithPayload(result)
@@ -169,9 +169,9 @@ func (c User) PatchUserFunc(repository domain.UserRepository) users.PatchUserHan
 
 		err := repository.UpdateUserByID(ctx, userID, p.UserPatch)
 		if err != nil {
-			c.logger.Error("get user by id error", zap.Error(err))
+			c.logger.Error(messages.ErrUpdateUser, zap.Error(err))
 			return users.NewPatchUserDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("cant update user"))
+				WithPayload(buildInternalErrorPayload(messages.ErrUpdateUser, err.Error()))
 		}
 		return users.NewPatchUserNoContent()
 	}
@@ -184,17 +184,18 @@ func (c User) AssignRoleToUserFunc(repository domain.UserRepository) users.Assig
 		userId := int(p.UserID)
 		if p.Data.RoleID == nil {
 			return users.NewAssignRoleToUserDefault(http.StatusBadRequest).
-				WithPayload(buildStringPayload("role id is required"))
+				WithPayload(buildInternalErrorPayload(messages.ErrRoleRequired, ""))
 		}
 		roleId := int(*p.Data.RoleID)
 
 		err := repository.SetUserRole(ctx, userId, roleId)
 		if err != nil {
-			c.logger.Error("set user role error", zap.Error(err))
-			return users.NewAssignRoleToUserDefault(http.StatusInternalServerError).WithPayload(buildErrorPayload(err))
+			c.logger.Error(messages.ErrSetUserRole, zap.Error(err))
+			return users.NewAssignRoleToUserDefault(http.StatusInternalServerError).
+				WithPayload(buildInternalErrorPayload(messages.ErrSetUserRole, err.Error()))
 		}
 
-		return users.NewAssignRoleToUserOK().WithPayload("role assigned")
+		return users.NewAssignRoleToUserOK().WithPayload(messages.MsgRoleAssigned)
 	}
 }
 
@@ -205,14 +206,14 @@ func (c User) GetUserById(repository domain.UserRepository) users.GetUserHandler
 		foundUser, err := repository.GetUserByID(ctx, id)
 		if err != nil {
 			return users.NewGetUserDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("cant find user by id"))
+				WithPayload(buildInternalErrorPayload(messages.ErrUserNotFound, ""))
 		}
 
 		userToResponse, err := mapUserInfo(foundUser)
 		if err != nil {
-			c.logger.Error("map user error", zap.Error(err))
+			c.logger.Error(messages.ErrMapUser, zap.Error(err))
 			return users.NewGetUserDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("map user error"))
+				WithPayload(buildInternalErrorPayload(messages.ErrMapUser, err.Error()))
 		}
 
 		return users.NewGetUserOK().WithPayload(userToResponse)
@@ -228,17 +229,17 @@ func (c User) GetUsersList(repository domain.UserRepository) users.GetAllUsersHa
 		orderColumn := utils.GetValueByPointerOrDefaultValue(p.OrderColumn, user.FieldID)
 		total, err := repository.UsersListTotal(ctx)
 		if err != nil {
-			c.logger.Error("failed get user total amount", zap.Error(err))
+			c.logger.Error(messages.ErrQueryTotalUsers, zap.Error(err))
 			return users.NewGetAllUsersDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("failed to get user total amount"))
+				WithPayload(buildInternalErrorPayload(messages.ErrQueryTotalUsers, err.Error()))
 		}
 		var allUsers []*ent.User
 		if total > 0 {
 			allUsers, err = repository.UserList(ctx, int(limit), int(offset), orderBy, orderColumn)
 			if err != nil {
-				c.logger.Error("failed get user list", zap.Error(err))
+				c.logger.Error(messages.ErrQueryUsers, zap.Error(err))
 				return users.NewGetAllUsersDefault(http.StatusInternalServerError).
-					WithPayload(buildStringPayload("failed to get user list"))
+					WithPayload(buildInternalErrorPayload(messages.ErrQueryUsers, err.Error()))
 			}
 		}
 
@@ -246,9 +247,9 @@ func (c User) GetUsersList(repository domain.UserRepository) users.GetAllUsersHa
 		for i, element := range allUsers {
 			userToResponse, errMap := mapUserInfo(element)
 			if errMap != nil {
-				c.logger.Error("map user error", zap.Error(errMap))
+				c.logger.Error(messages.ErrMapUser, zap.Error(errMap))
 				return users.NewGetAllUsersDefault(http.StatusInternalServerError).
-					WithPayload(buildStringPayload("map user error"))
+					WithPayload(buildInternalErrorPayload(messages.ErrMapUser, errMap.Error()))
 			}
 			usersToResponse[i] = userToResponse
 		}
@@ -269,9 +270,9 @@ func (c User) DeleteCurrentUser(repository domain.UserRepository) users.DeleteCu
 
 		err := repository.Delete(ctx, userID)
 		if err != nil {
-			c.logger.Error("error during deleting user", zap.Error(err))
+			c.logger.Error(messages.ErrDeleteUser, zap.Error(err))
 			return users.NewDeleteCurrentUserDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("can't delete user"))
+				WithPayload(buildInternalErrorPayload(messages.ErrDeleteUser, err.Error()))
 		}
 
 		return users.NewDeleteCurrentUserOK()
@@ -289,26 +290,26 @@ func (c User) DeleteUser(repo domain.UserRepository) users.DeleteUserHandlerFunc
 			c.logger.Error(fmt.Sprintf("retrieving user by ID %d", userID), zap.Error(err))
 			if ent.IsNotFound(err) {
 				return users.NewDeleteUserNotFound().
-					WithPayload(buildStringPayload("User not found"))
+					WithPayload(buildNotFoundErrorPayload(messages.ErrUserNotFound, ""))
 			}
 			return users.NewDeleteUserDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Unexpected error"))
+				WithPayload(buildInternalErrorPayload(messages.ErrDeleteUser, err.Error()))
 		}
 
 		if !user.IsReadonly {
-			c.logger.Error("User must be readonly for deletion", zap.Int("userID", userID))
+			c.logger.Error(messages.ErrDeleteUserNotRO, zap.Int("userID", userID))
 			return users.NewDeleteUserDefault(http.StatusForbidden).
-				WithPayload(buildStringPayload("User must be readonly for deletion"))
+				WithPayload(buildForbiddenErrorPayload(messages.ErrDeleteUserNotRO, ""))
 		}
 
 		if err := repo.Delete(ctx, userID); err != nil {
 			c.logger.Error("deleting user", zap.Error(err))
 			if ent.IsNotFound(err) {
 				return users.NewDeleteUserNotFound().
-					WithPayload(buildStringPayload("User not found"))
+					WithPayload(buildNotFoundErrorPayload(messages.ErrUserNotFound, ""))
 			}
 			return users.NewDeleteUserDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Unexpected error"))
+				WithPayload(buildInternalErrorPayload(messages.ErrDeleteUser, err.Error()))
 		}
 
 		c.logger.Info("User deleted successfully", zap.Int("userID", userID), zap.Int("deletedByUserID", deletedByUserID))
@@ -322,32 +323,32 @@ func (c User) ChangePassword(repo domain.UserRepository) users.ChangePasswordHan
 		userID := int(principal.ID)
 
 		if p.PasswordPatch == nil {
-			c.logger.Error("password patch is nil", zap.Any("principal", principal))
+			c.logger.Error(messages.ErrPasswordPatchEmpty, zap.Any("principal", principal))
 			return users.NewChangePasswordDefault(http.StatusBadRequest).
-				WithPayload(buildStringPayload("Password patch is nil"))
+				WithPayload(buildBadRequestErrorPayload(messages.ErrPasswordPatchEmpty, ""))
 		}
 		//TODO: add validation for password or ask frontend to do it
 		if p.PasswordPatch.OldPassword == p.PasswordPatch.NewPassword {
 			c.logger.Error("old and new passwords are the same", zap.Any("principal", principal))
 			return users.NewChangePasswordDefault(http.StatusBadRequest).
-				WithPayload(buildStringPayload("Old and new passwords are the same"))
+				WithPayload(buildBadRequestErrorPayload(messages.ErrPasswordsAreSame, ""))
 		}
 		requestedUser, err := repo.GetUserByID(ctx, userID)
 		if err != nil {
 			c.logger.Error("getting user failed", zap.Error(err))
 			return users.NewChangePasswordDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Can't get user by id"))
+				WithPayload(buildInternalErrorPayload(messages.ErrUserPasswordChange, err.Error()))
 		}
 		expectedPasswordHash := requestedUser.Password
 		if err = bcrypt.CompareHashAndPassword([]byte(expectedPasswordHash), []byte(p.PasswordPatch.OldPassword)); err != nil {
-			c.logger.Error("wrong password", zap.Error(err))
+			c.logger.Error(messages.ErrWrongPassword, zap.Error(err))
 			return users.NewChangePasswordDefault(http.StatusForbidden).
-				WithPayload(buildStringPayload("Wrong password"))
+				WithPayload(buildForbiddenErrorPayload(messages.ErrWrongPassword, ""))
 		}
 		if err = repo.ChangePasswordByLogin(ctx, requestedUser.Login, p.PasswordPatch.NewPassword); err != nil {
 			c.logger.Error("error while changing password", zap.Error(err))
 			return users.NewChangePasswordDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Error while changing password"))
+				WithPayload(buildInternalErrorPayload(messages.ErrUserPasswordChange, err.Error()))
 		}
 		return users.NewChangePasswordNoContent()
 	}
@@ -361,13 +362,13 @@ func (c User) UpdateReadonlyAccess(repo domain.UserRepository) users.UpdateReado
 		isReadonly := p.Body.IsReadonly
 
 		if err := repo.SetIsReadonly(ctx, userID, isReadonly); err != nil {
-			c.logger.Error("error while updating readonly access", zap.Error(err))
+			c.logger.Error(messages.ErrUpdateROAccess, zap.Error(err))
 			if ent.IsNotFound(err) {
 				return users.NewUpdateReadonlyAccessNotFound().
-					WithPayload(buildStringPayload("User not found"))
+					WithPayload(buildNotFoundErrorPayload(messages.ErrUserNotFound, ""))
 			}
 			return users.NewUpdateReadonlyAccessDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Unexpected error"))
+				WithPayload(buildInternalErrorPayload(messages.ErrUpdateROAccess, err.Error()))
 		}
 
 		if isReadonly {
@@ -387,23 +388,23 @@ func (c User) ChangeEmail(repo domain.UserRepository,
 		userID := int(principal.ID)
 
 		if p.EmailPatch == nil {
-			c.logger.Error("email patch is nil", zap.Any("principal", principal))
+			c.logger.Error(messages.ErrEmailPatchEmpty, zap.Any("principal", principal))
 			return users.NewChangeEmailDefault(http.StatusBadRequest).
-				WithPayload(buildStringPayload("Email patch is nil"))
+				WithPayload(buildBadRequestErrorPayload(messages.ErrEmailPatchEmpty, ""))
 		}
 
 		requestedUser, err := repo.GetUserByID(ctx, userID)
 		if err != nil {
 			c.logger.Error("getting user for changing email failed", zap.Error(err))
 			return users.NewChangeEmailDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Can't get user by id"))
+				WithPayload(buildInternalErrorPayload(messages.ErrChangeEmail, err.Error()))
 		}
 
 		err = changeEmailService.SendEmailConfirmationLink(ctx, requestedUser.Login, p.EmailPatch.NewEmail)
 		if err != nil {
 			c.logger.Error("error while sending link for confirmation new email", zap.Error(err))
 			return users.NewChangeEmailDefault(http.StatusInternalServerError).
-				WithPayload(buildStringPayload("Can't send link for confirmation new email"))
+				WithPayload(buildInternalErrorPayload(messages.ErrNewEmailConfirmation, err.Error()))
 		}
 
 		return users.NewChangeEmailNoContent()
diff --git a/internal/integration-tests/activeareas/integration_test.go b/internal/integration-tests/activeareas/integration_test.go
index 27fa5d48..a9b998af 100644
--- a/internal/integration-tests/activeareas/integration_test.go
+++ b/internal/integration-tests/activeareas/integration_test.go
@@ -11,6 +11,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/client/active_areas"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	utils "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/integration-tests/common"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 )
 
 func TestIntegration_GetActiveAreas(t *testing.T) {
@@ -39,8 +40,11 @@ func TestIntegration_GetActiveAreas(t *testing.T) {
 		require.Error(t, err)
 
 		errExp := active_areas.NewGetAllActiveAreasDefault(http.StatusUnauthorized)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		msgExp := "unauthenticated for invalid credentials"
+		codeExp := int32(http.StatusUnauthorized)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
 		}
 		assert.Equal(t, errExp, err)
 	})
@@ -53,8 +57,10 @@ func TestIntegration_GetActiveAreas(t *testing.T) {
 		require.Error(t, err)
 
 		errExp := active_areas.NewGetAllActiveAreasDefault(http.StatusUnauthorized)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		codeExp := int32(http.StatusUnauthorized)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
 		}
 		assert.Equal(t, errExp, err)
 	})
diff --git a/internal/integration-tests/category/category_test.go b/internal/integration-tests/category/category_test.go
index 93eaa81c..7edafa76 100644
--- a/internal/integration-tests/category/category_test.go
+++ b/internal/integration-tests/category/category_test.go
@@ -17,6 +17,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/client/categories"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	utils "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/integration-tests/common"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 )
 
 var (
@@ -61,7 +62,12 @@ func TestIntegration_GetAllCategories(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := categories.NewGetAllCategoriesDefault(http.StatusUnprocessableEntity)
-		wantErr.Payload = &models.Error{Data: nil}
+		msgExp := "order_column in query should be one of [id name]"
+		codeExp := int32(606)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 }
@@ -88,7 +94,11 @@ func TestIntegration_CreateCategory(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := categories.NewCreateNewCategoryDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -163,9 +173,12 @@ func TestIntegration_GetCategoryByID(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := categories.NewGetCategoryByIDDefault(http.StatusInternalServerError)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{
-			Message: "failed to get category",
-		}}
+		codeExp := int32(http.StatusInternalServerError)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrGetCategory,
+			Details: "ent: category not found",
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -175,7 +188,11 @@ func TestIntegration_GetCategoryByID(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := categories.NewGetCategoryByIDDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 }
@@ -257,9 +274,12 @@ func TestIntegration_EditCategory(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := categories.NewUpdateCategoryDefault(http.StatusInternalServerError)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{
-			Message: "cant update category",
-		}}
+		codeExp := int32(http.StatusInternalServerError)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrUpdateCategory,
+			Details: "ent: category not found",
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -279,7 +299,11 @@ func TestIntegration_EditCategory(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := categories.NewUpdateCategoryDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -289,7 +313,12 @@ func TestIntegration_EditCategory(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := categories.NewUpdateCategoryDefault(http.StatusUnprocessableEntity)
-		wantErr.Payload = &models.Error{Data: nil}
+		msgExp := "updateCategory in body is required"
+		codeExp := int32(602)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 }
@@ -307,7 +336,12 @@ func TestIntegration_DeleteCategory(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := categories.NewDeleteCategoryDefault(http.StatusInternalServerError)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{Message: "delete category failed"}}
+		codeExp := int32(http.StatusInternalServerError)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrDeleteCategory,
+			Details: "ent: category not found",
+		}
 		assert.Equal(t, wantErr, gotErr)
 
 		_, gotErr = client.Categories.DeleteCategory(categories.NewDeleteCategoryParamsWithContext(ctx).WithCategoryID(-33), auth)
@@ -322,7 +356,11 @@ func TestIntegration_DeleteCategory(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := categories.NewDeleteCategoryDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
diff --git a/internal/integration-tests/equipment/integration_test.go b/internal/integration-tests/equipment/integration_test.go
index 8d31a3e4..116c5068 100644
--- a/internal/integration-tests/equipment/integration_test.go
+++ b/internal/integration-tests/equipment/integration_test.go
@@ -23,8 +23,8 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/client/photos"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/client/subcategories"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
-	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/handlers"
 	utils "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/integration-tests/common"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
 )
 
@@ -128,9 +128,12 @@ func TestIntegration_CreateEquipment(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := equipment.NewCreateNewEquipmentDefault(500)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{
-			Message: "Error while creating equipment",
-		}}
+		codeExp := int32(http.StatusInternalServerError)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrCreateEquipment,
+			Details: "ent: constraint failed: ERROR: insert or update on table \"equipment\" violates foreign key constraint \"equipment_photo_equipments_fkey\" (SQLSTATE 23503)",
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -146,7 +149,11 @@ func TestIntegration_CreateEquipment(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := equipment.NewCreateNewEquipmentDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 }
@@ -179,7 +186,11 @@ func TestIntegration_GetAllEquipment(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := equipment.NewGetAllEquipmentDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 }
@@ -239,8 +250,13 @@ func TestIntegration_GetEquipment(t *testing.T) {
 		_, gotErr := client.Equipment.GetEquipment(params, auth)
 		require.Error(t, gotErr)
 
-		wantErr := equipment.NewGetEquipmentDefault(500)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{Message: "Error while getting equipment"}}
+		wantErr := equipment.NewGetEquipmentDefault(http.StatusInternalServerError)
+		codeExp := int32(http.StatusInternalServerError)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrGetEquipment,
+			Details: "ent: equipment not found",
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -254,7 +270,11 @@ func TestIntegration_GetEquipment(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := equipment.NewGetEquipmentDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 }
@@ -316,7 +336,11 @@ func TestIntegration_FindEquipment(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := equipment.NewFindEquipmentDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -371,8 +395,13 @@ func TestIntegration_EditEquipment(t *testing.T) {
 		_, gotErr := client.Equipment.EditEquipment(params, auth)
 		require.Error(t, gotErr)
 
-		wantErr := equipment.NewEditEquipmentDefault(500)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{Message: "Error while updating equipment"}}
+		wantErr := equipment.NewEditEquipmentDefault(http.StatusInternalServerError)
+		codeExp := int32(http.StatusInternalServerError)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrUpdateEquipment,
+			Details: "ent: equipment not found",
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -386,7 +415,11 @@ func TestIntegration_EditEquipment(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := equipment.NewEditEquipmentDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 }
@@ -422,15 +455,20 @@ func TestIntegration_ArchiveEquipment(t *testing.T) {
 		require.Error(t, gotErr)
 		fmt.Print(resp)
 
-		wantedErr := equipment.NewArchiveEquipmentNotFound()
-		wantedErr.Payload = &models.Error{Data: &models.ErrorData{Message: handlers.EquipmentNotFoundMsg}}
+		wantErr := equipment.NewArchiveEquipmentNotFound()
+		codeExp := int32(http.StatusNotFound)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrEquipmentNotFound,
+		}
 
-		require.Equal(t, wantedErr, gotErr)
+		require.Equal(t, wantErr, gotErr)
 	})
 
 	t.Run("Archive Equipment with active orders", func(t *testing.T) {
 		orStartDate, orEndDate := time.Now(), time.Now().AddDate(0, 0, 1)
 		orderID, err := createOrder(ctx, client, auth, created.Payload.ID, orStartDate, orEndDate)
+		require.NoError(t, err)
 		params := equipment.NewArchiveEquipmentParamsWithContext(ctx).WithEquipmentID(*created.Payload.ID)
 		var res *equipment.ArchiveEquipmentNoContent
 		res, err = client.Equipment.ArchiveEquipment(params, auth)
@@ -448,9 +486,13 @@ func TestIntegration_ArchiveEquipment(t *testing.T) {
 		_, gotErr := client.Equipment.ArchiveEquipment(params, utils.AuthInfoFunc(&token))
 		require.Error(t, gotErr)
 
-		wantedErr := equipment.NewArchiveEquipmentDefault(http.StatusUnauthorized)
-		wantedErr.Payload = &models.Error{Data: nil}
-		assert.Equal(t, wantedErr, gotErr)
+		wantErr := equipment.NewArchiveEquipmentDefault(http.StatusUnauthorized)
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
+		assert.Equal(t, wantErr, gotErr)
 	})
 
 	// todo: test for archive equipment with non-default status
@@ -545,7 +587,11 @@ func TestIntegration_BlockEquipment(t *testing.T) {
 		require.Error(t, err)
 
 		wantErr := equipment.NewBlockEquipmentNotFound()
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{Message: handlers.EquipmentNotFoundMsg}}
+		codeExp := int32(http.StatusNotFound)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrEquipmentNotFound,
+		}
 		assert.Equal(t, wantErr, err)
 	})
 
@@ -562,9 +608,11 @@ func TestIntegration_BlockEquipment(t *testing.T) {
 		require.Error(t, err)
 
 		wantErr := equipment.NewBlockEquipmentDefault(http.StatusForbidden)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{
-			Message: "You don't have rights to block the equipment",
-		}}
+		codeExp := int32(http.StatusForbidden)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrEquipmentBlockForbidden,
+		}
 		assert.Equal(t, wantErr, err)
 	})
 
@@ -581,9 +629,11 @@ func TestIntegration_BlockEquipment(t *testing.T) {
 		require.Error(t, err)
 
 		wantErr := equipment.NewBlockEquipmentDefault(http.StatusForbidden)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{
-			Message: "You don't have rights to block the equipment",
-		}}
+		codeExp := int32(http.StatusForbidden)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrEquipmentBlockForbidden,
+		}
 		assert.Equal(t, wantErr, err)
 	})
 
@@ -600,6 +650,27 @@ func TestIntegration_BlockEquipment(t *testing.T) {
 		require.NoError(t, err)
 		require.True(t, res.IsCode(http.StatusNoContent))
 	})
+
+	t.Run("Block Equipment is failed, endDate before startDate", func(t *testing.T) {
+		tokens := utils.ManagerUserLogin(t)
+		auth := utils.AuthInfoFunc(tokens.GetPayload().AccessToken)
+		params := equipment.NewBlockEquipmentParamsWithContext(ctx).WithEquipmentID(*eq.Payload.ID)
+		params.Data = &models.ChangeEquipmentStatusToBlockedRequest{
+			StartDate: strfmt.DateTime(endDate),
+			EndDate:   strfmt.DateTime(startDate),
+		}
+
+		_, err := client.Equipment.BlockEquipment(params, auth)
+		require.Error(t, err)
+
+		wantErr := equipment.NewBlockEquipmentDefault(http.StatusBadRequest)
+		codeExp := int32(http.StatusBadRequest)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrStartDateAfterEnd,
+		}
+		assert.Equal(t, wantErr, err)
+	})
 }
 
 func TestIntegration_DeleteEquipment(t *testing.T) {
@@ -638,9 +709,12 @@ func TestIntegration_DeleteEquipment(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := equipment.NewDeleteEquipmentDefault(500)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{
-			Message: "Error while getting equipment",
-		}}
+		codeExp := int32(http.StatusInternalServerError)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrDeleteEquipment,
+			Details: "ent: equipment not found",
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -653,7 +727,11 @@ func TestIntegration_DeleteEquipment(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := equipment.NewDeleteEquipmentDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 }
@@ -684,9 +762,11 @@ func TestIntegration_UnblockEquipment(t *testing.T) {
 		require.Error(t, err)
 
 		wantErr := equipment.NewUnblockEquipmentDefault(http.StatusForbidden)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{
-			Message: "You don't have rights to unblock the equipment",
-		}}
+		codeExp := int32(http.StatusForbidden)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrEquipmentUnblockForbidden,
+		}
 		assert.Equal(t, wantErr, err)
 	})
 
@@ -699,9 +779,11 @@ func TestIntegration_UnblockEquipment(t *testing.T) {
 		require.Error(t, err)
 
 		wantErr := equipment.NewUnblockEquipmentDefault(http.StatusForbidden)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{
-			Message: "You don't have rights to unblock the equipment",
-		}}
+		codeExp := int32(http.StatusForbidden)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrEquipmentUnblockForbidden,
+		}
 		assert.Equal(t, wantErr, err)
 	})
 
@@ -748,7 +830,11 @@ func TestIntegration_UnblockEquipment(t *testing.T) {
 		require.Error(t, err)
 
 		wantErr := equipment.NewUnblockEquipmentNotFound()
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{Message: handlers.EquipmentNotFoundMsg}}
+		codeExp := int32(http.StatusNotFound)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrEquipmentNotFound,
+		}
 		assert.Equal(t, wantErr, err)
 	})
 }
diff --git a/internal/integration-tests/equipmentstatusname/equipment_status_name_test.go b/internal/integration-tests/equipmentstatusname/equipment_status_name_test.go
index e86a75be..29afdf7d 100644
--- a/internal/integration-tests/equipmentstatusname/equipment_status_name_test.go
+++ b/internal/integration-tests/equipmentstatusname/equipment_status_name_test.go
@@ -11,6 +11,7 @@ import (
 	eqStatusName "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/client/equipment_status_name"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	utils "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/integration-tests/common"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
 )
 
@@ -41,7 +42,11 @@ func TestIntegration_GetStatuses(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := eqStatusName.NewListEquipmentStatusNamesDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 }
@@ -75,9 +80,12 @@ func TestIntegration_GetStatus(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := eqStatusName.NewGetEquipmentStatusNameDefault(500)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{
-			Message: "can't get status",
-		}}
+		codeExp := int32(http.StatusInternalServerError)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrGetEqStatus,
+			Details: "ent: equipment_status_name not found",
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -90,7 +98,11 @@ func TestIntegration_GetStatus(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := eqStatusName.NewGetEquipmentStatusNameDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 }
@@ -128,8 +140,13 @@ func TestIntegration_PostStatus(t *testing.T) {
 		_, gotErr := client.EquipmentStatusName.PostEquipmentStatusName(params, utils.AuthInfoFunc(token))
 		require.Error(t, gotErr)
 
-		wantErr := eqStatusName.NewPostEquipmentStatusNameDefault(500)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{Message: "can't create status"}}
+		wantErr := eqStatusName.NewPostEquipmentStatusNameDefault(http.StatusInternalServerError)
+		codeExp := int32(http.StatusInternalServerError)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrCreateEqStatus,
+			Details: "ent: constraint failed: ERROR: duplicate key value violates unique constraint \"equipment_status_names_name_key\" (SQLSTATE 23505)",
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -144,7 +161,11 @@ func TestIntegration_PostStatus(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := eqStatusName.NewPostEquipmentStatusNameDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 }
@@ -178,8 +199,13 @@ func TestIntegration_DeleteStatus(t *testing.T) {
 		_, gotErr := client.EquipmentStatusName.DeleteEquipmentStatusName(params, utils.AuthInfoFunc(token))
 		require.Error(t, gotErr)
 
-		wantErr := eqStatusName.NewDeleteEquipmentStatusNameDefault(500)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{Message: "can't delete status"}}
+		wantErr := eqStatusName.NewDeleteEquipmentStatusNameDefault(http.StatusInternalServerError)
+		codeExp := int32(http.StatusInternalServerError)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrDeleteEqStatus,
+			Details: "ent: equipment_status_name not found",
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -189,8 +215,13 @@ func TestIntegration_DeleteStatus(t *testing.T) {
 		_, gotErr := client.EquipmentStatusName.DeleteEquipmentStatusName(params, utils.AuthInfoFunc(token))
 		require.Error(t, gotErr)
 
-		wantErr := eqStatusName.NewDeleteEquipmentStatusNameDefault(500)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{Message: "can't delete status"}}
+		wantErr := eqStatusName.NewDeleteEquipmentStatusNameDefault(http.StatusInternalServerError)
+		codeExp := int32(http.StatusInternalServerError)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrDeleteEqStatus,
+			Details: "ent: equipment_status_name not found",
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -203,7 +234,11 @@ func TestIntegration_DeleteStatus(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := eqStatusName.NewDeleteEquipmentStatusNameDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 }
diff --git a/internal/integration-tests/orders/order_test.go b/internal/integration-tests/orders/order_test.go
index 5b543081..0280be3d 100644
--- a/internal/integration-tests/orders/order_test.go
+++ b/internal/integration-tests/orders/order_test.go
@@ -14,6 +14,7 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/client/subcategories"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
 
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/ent/order"
@@ -91,7 +92,11 @@ func TestIntegration_CreateOrder(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := orders.NewCreateOrderDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -110,8 +115,12 @@ func TestIntegration_CreateOrder(t *testing.T) {
 		_, gotErr := client.Orders.CreateOrder(params, auth)
 		require.Error(t, gotErr)
 
-		wantErr := orders.NewCreateOrderDefault(http.StatusInternalServerError)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{Message: "start date should be before end date"}}
+		wantErr := orders.NewCreateOrderDefault(http.StatusBadRequest)
+		codeExp := int32(http.StatusBadRequest)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrStartDateAfterEnd,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -130,8 +139,12 @@ func TestIntegration_CreateOrder(t *testing.T) {
 		_, gotErr := client.Orders.CreateOrder(params, auth)
 		require.Error(t, gotErr)
 
-		wantErr := orders.NewCreateOrderDefault(http.StatusInternalServerError)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{Message: "small rent period"}}
+		wantErr := orders.NewCreateOrderDefault(http.StatusBadRequest)
+		codeExp := int32(http.StatusBadRequest)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrSmallRentPeriod,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -151,7 +164,12 @@ func TestIntegration_CreateOrder(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := orders.NewCreateOrderDefault(http.StatusInternalServerError)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{Message: "too big reservation period"}}
+		codeExp := int32(http.StatusInternalServerError)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrMapOrder,
+			Details: "too big reservation period",
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -169,7 +187,12 @@ func TestIntegration_CreateOrder(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := orders.NewCreateOrderDefault(http.StatusUnprocessableEntity)
-		wantErr.Payload = &models.Error{Data: nil}
+		msgExp := "equipment_id in body is required"
+		codeExp := int32(602)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -306,7 +329,11 @@ func TestIntegration_GetUserOrders(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := orders.NewGetUserOrdersDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -326,7 +353,12 @@ func TestIntegration_GetUserOrders(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := orders.NewGetUserOrdersDefault(http.StatusUnprocessableEntity)
-		wantErr.Payload = &models.Error{Data: nil}
+		msgExp := "order_column in query should be one of [id rent_start]"
+		codeExp := int32(606)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
diff --git a/internal/integration-tests/passwordreset/integration_test.go b/internal/integration-tests/passwordreset/integration_test.go
index 0c7b939a..8e30a1df 100644
--- a/internal/integration-tests/passwordreset/integration_test.go
+++ b/internal/integration-tests/passwordreset/integration_test.go
@@ -11,6 +11,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/client/password_reset"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	utils "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/integration-tests/common"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 )
 
 func TestIntegration_PasswordReset(t *testing.T) {
@@ -36,7 +37,7 @@ func TestIntegration_PasswordReset(t *testing.T) {
 		require.NoError(t, err)
 
 		want := &password_reset.SendLinkByLoginOK{
-			Payload: models.PasswordResetResponse("Check your email for a reset link"),
+			Payload: models.PasswordResetResponse("check your email for a reset link"),
 		}
 		assert.Equal(t, want, got)
 	})
@@ -51,8 +52,10 @@ func TestIntegration_PasswordReset(t *testing.T) {
 		require.Error(t, err)
 
 		errExp := password_reset.NewSendLinkByLoginDefault(http.StatusBadRequest)
-		errExp.Payload = &models.Error{
-			Data: &models.ErrorData{Message: "Login is required"},
+		codeExp := int32(http.StatusBadRequest)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrLoginRequired,
 		}
 		assert.Equal(t, errExp, err)
 	})
@@ -67,7 +70,7 @@ func TestIntegration_PasswordReset(t *testing.T) {
 		require.NoError(t, err)
 
 		want := &password_reset.SendLinkByLoginOK{
-			Payload: models.PasswordResetResponse("Check your email for a reset link"),
+			Payload: models.PasswordResetResponse("check your email for a reset link"),
 		}
 		assert.Equal(t, want, got)
 	})
diff --git a/internal/integration-tests/petkind/create_integration_test.go b/internal/integration-tests/petkind/create_integration_test.go
index 27d4a056..aa39c560 100644
--- a/internal/integration-tests/petkind/create_integration_test.go
+++ b/internal/integration-tests/petkind/create_integration_test.go
@@ -9,6 +9,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/client/pet_kind"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	utils "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/integration-tests/common"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -53,8 +54,11 @@ func TestIntegration_PetKind(t *testing.T) {
 		require.Error(t, err)
 
 		errExp := pet_kind.NewCreateNewPetKindDefault(http.StatusUnprocessableEntity)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		msgExp := "name in body is required"
+		codeExp := int32(602)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
 		}
 		assert.Equal(t, errExp, err)
 	})
@@ -66,8 +70,11 @@ func TestIntegration_PetKind(t *testing.T) {
 		require.Error(t, err)
 
 		errExp := pet_kind.NewCreateNewPetKindDefault(http.StatusUnauthorized)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		msgExp := "unauthenticated for invalid credentials"
+		codeExp := int32(http.StatusUnauthorized)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
 		}
 		assert.Equal(t, errExp, err)
 	})
@@ -80,8 +87,10 @@ func TestIntegration_PetKind(t *testing.T) {
 		require.Error(t, err)
 
 		errExp := pet_kind.NewCreateNewPetKindDefault(http.StatusUnauthorized)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		codeExp := int32(http.StatusUnauthorized)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
 		}
 		assert.Equal(t, errExp, err)
 	})
diff --git a/internal/integration-tests/petkind/get_integration_test.go b/internal/integration-tests/petkind/get_integration_test.go
index b5b2bc21..57b3539a 100644
--- a/internal/integration-tests/petkind/get_integration_test.go
+++ b/internal/integration-tests/petkind/get_integration_test.go
@@ -122,5 +122,5 @@ func TestIntegration_DeletePetKind(t *testing.T) {
 	kind, err := client.PetKind.DeletePetKind(params, utils.AuthInfoFunc(token))
 	require.NoError(t, err)
 
-	assert.Equal(t, kind.GetPayload(), "Pet kind deleted")
+	assert.Equal(t, kind.GetPayload(), "pet kind deleted")
 }
diff --git a/internal/integration-tests/petsize/create_integration_test.go b/internal/integration-tests/petsize/create_integration_test.go
index 437d2fe5..9e663a8b 100644
--- a/internal/integration-tests/petsize/create_integration_test.go
+++ b/internal/integration-tests/petsize/create_integration_test.go
@@ -8,6 +8,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/client/pet_size"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	utils "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/integration-tests/common"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -60,8 +61,11 @@ func TestIntegration_PetSize(t *testing.T) {
 		require.Error(t, err)
 
 		errExp := pet_size.NewCreateNewPetSizeDefault(http.StatusUnprocessableEntity)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		msgExp := "name in body is required"
+		codeExp := int32(602)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
 		}
 		assert.Equal(t, errExp, err)
 	})
@@ -73,8 +77,11 @@ func TestIntegration_PetSize(t *testing.T) {
 		require.Error(t, err)
 
 		errExp := pet_size.NewCreateNewPetSizeDefault(http.StatusUnauthorized)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		msgExp := "unauthenticated for invalid credentials"
+		codeExp := int32(http.StatusUnauthorized)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
 		}
 		assert.Equal(t, errExp, err)
 	})
@@ -87,8 +94,10 @@ func TestIntegration_PetSize(t *testing.T) {
 		require.Error(t, err)
 
 		errExp := pet_size.NewCreateNewPetSizeDefault(http.StatusUnauthorized)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		codeExp := int32(http.StatusUnauthorized)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
 		}
 		assert.Equal(t, errExp, err)
 	})
diff --git a/internal/integration-tests/petsize/get_integration_test.go b/internal/integration-tests/petsize/get_integration_test.go
index c15b34d1..9d1ec8e9 100644
--- a/internal/integration-tests/petsize/get_integration_test.go
+++ b/internal/integration-tests/petsize/get_integration_test.go
@@ -83,7 +83,7 @@ func TestIntegration_DeletePetSize(t *testing.T) {
 	res, err := client.PetSize.DeletePetSize(params, utils.AuthInfoFunc(token))
 	require.NoError(t, err)
 
-	assert.Equal(t, "Pet size deleted", res.GetPayload())
+	assert.Equal(t, "pet size deleted", res.GetPayload())
 }
 
 func getSizeIDByName(ctx context.Context, client *client.Be, token *string, petSizeName string) (*int64, error) {
diff --git a/internal/integration-tests/photos/integration_test.go b/internal/integration-tests/photos/integration_test.go
index 07776abb..375795e6 100644
--- a/internal/integration-tests/photos/integration_test.go
+++ b/internal/integration-tests/photos/integration_test.go
@@ -16,6 +16,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/client/photos"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/integration-tests/common"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 )
 
 var (
@@ -93,8 +94,8 @@ func TestIntegration_PhotosUpload(t *testing.T) {
 		require.True(t, errors.As(err, &phErr))
 
 		wantMessage := "Wrong file format. File should be jpg or jpeg"
-		require.NotNil(t, phErr.Payload.Data)
-		assert.Equal(t, wantMessage, phErr.Payload.Data.Message)
+		require.NotNil(t, phErr.Payload.Message)
+		assert.Equal(t, wantMessage, *phErr.Payload.Message)
 		f.Close()
 	})
 
@@ -106,9 +107,14 @@ func TestIntegration_PhotosUpload(t *testing.T) {
 		_, err = beClient.Photos.CreateNewPhoto(params, auth)
 		require.Error(t, err)
 
-		var phErr *photos.CreateNewPhotoBadRequest
-		require.True(t, errors.As(err, &phErr))
-		assert.Nil(t, phErr.Payload.Data)
+		wantErr := photos.NewCreateNewPhotoBadRequest()
+		msgExp := "multipart: NextPart: EOF"
+		codeExp := int32(http.StatusBadRequest)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
+		}
+		assert.Equal(t, wantErr, err)
 
 		emptyFile.Close()
 		require.NoError(t, os.Remove("empty.jpeg"))
@@ -125,7 +131,11 @@ func TestIntegration_PhotosUpload(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := photos.NewCreateNewPhotoDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 		f.Close()
 	})
@@ -155,7 +165,11 @@ func TestIntegration_DeletePhoto(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := photos.NewDeletePhotoDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -164,7 +178,12 @@ func TestIntegration_DeletePhoto(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := photos.NewDeletePhotoDefault(http.StatusUnprocessableEntity)
-		wantErr.Payload = &models.Error{Data: nil}
+		msgExp := "equipmentId in path must be of type int64: \"photos\""
+		codeExp := int32(601)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 
@@ -173,19 +192,22 @@ func TestIntegration_DeletePhoto(t *testing.T) {
 		require.NoError(t, err)
 
 		got := result.Payload
-		want := "Photo deleted"
+		want := "photo deleted"
 		assert.Equal(t, want, got)
 	})
 
 	t.Run("Delete Photo failed: trying to delete again the same photo, photo not found", func(t *testing.T) {
-		_, err = beClient.Photos.DeletePhoto(photos.NewDeletePhotoParamsWithContext(ctx).WithPhotoID(*res.Payload.Data.ID), auth)
-		require.Error(t, err)
-
-		var phErr *photos.DeletePhotoDefault
-		ok := errors.As(err, &phErr)
-		require.True(t, ok)
+		_, gotErr := beClient.Photos.DeletePhoto(photos.NewDeletePhotoParamsWithContext(ctx).WithPhotoID(*res.Payload.Data.ID), auth)
+		require.Error(t, gotErr)
 
-		assert.Contains(t, phErr.Payload.Data.Message, "photo not found")
+		wantErr := photos.NewDeletePhotoDefault(http.StatusInternalServerError)
+		codeExp := int32(http.StatusInternalServerError)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrDeletePhoto,
+			Details: "ent: photo not found",
+		}
+		assert.Equal(t, wantErr, gotErr)
 	})
 
 	f.Close()
@@ -252,20 +274,28 @@ func TestIntegration_PhotosDownload(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := photos.NewDownloadPhotoDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 		f.Close()
 	})
 
 	t.Run("Download Photo failed: photoID not provided", func(t *testing.T) {
-		_, err := beClient.Photos.DownloadPhoto(photos.NewDownloadPhotoParamsWithContext(ctx), auth, io.Discard)
-		require.Error(t, err)
-
-		var phErr *photos.DownloadPhotoDefault
-		require.True(t, errors.As(err, &phErr))
+		_, gotErr := beClient.Photos.DownloadPhoto(photos.NewDownloadPhotoParamsWithContext(ctx), auth, io.Discard)
+		require.Error(t, gotErr)
 
-		assert.Equal(t, http.StatusInternalServerError, phErr.Code())
-		assert.Contains(t, phErr.Payload.Data.Message, "photo not found")
+		wantErr := photos.NewDownloadPhotoDefault(http.StatusInternalServerError)
+		msgExp := "failed to get photo"
+		codeExp := int32(http.StatusInternalServerError)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
+			Details: "ent: photo not found",
+		}
+		assert.Equal(t, wantErr, gotErr)
 	})
 }
 
@@ -328,7 +358,11 @@ func TestIntegration_PhotoGet(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := photos.NewGetPhotoDefault(http.StatusUnauthorized)
-		wantErr.Payload = &models.Error{Data: nil}
+		codeExp := int32(http.StatusUnauthorized)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 		f.Close()
 	})
@@ -338,7 +372,12 @@ func TestIntegration_PhotoGet(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := photos.NewGetPhotoDefault(http.StatusUnprocessableEntity)
-		wantErr.Payload = &models.Error{Data: nil}
+		msgExp := "equipmentId in path must be of type int64: \"photos\""
+		codeExp := int32(601)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 }
diff --git a/internal/integration-tests/registrationconfirm/integration_test.go b/internal/integration-tests/registrationconfirm/integration_test.go
index d4821237..405572b1 100644
--- a/internal/integration-tests/registrationconfirm/integration_test.go
+++ b/internal/integration-tests/registrationconfirm/integration_test.go
@@ -8,6 +8,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/client/registration_confirm"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	utils "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/integration-tests/common"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -53,8 +54,10 @@ func TestIntegration_SendConfirmLink(t *testing.T) {
 		require.Error(t, err)
 
 		errExp := registration_confirm.NewSendRegistrationConfirmLinkByLoginDefault(http.StatusInternalServerError)
-		errExp.Payload = &models.Error{
-			Data: &models.ErrorData{Message: "Can't find this user, registration confirmation link wasn't send"},
+		codeExp := int32(http.StatusInternalServerError)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrRegistrationCannotFindUser,
 		}
 		assert.Equal(t, errExp, err)
 	})
diff --git a/internal/integration-tests/roles/integration_test.go b/internal/integration-tests/roles/integration_test.go
index f0f70b37..a93b3ee4 100644
--- a/internal/integration-tests/roles/integration_test.go
+++ b/internal/integration-tests/roles/integration_test.go
@@ -8,6 +8,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/client/roles"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	utils "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/integration-tests/common"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -39,8 +40,11 @@ func TestIntegration_GetRoles(t *testing.T) {
 		require.Error(t, err)
 
 		errExp := roles.NewGetRolesDefault(http.StatusUnauthorized)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		msgExp := "unauthenticated for invalid credentials"
+		codeExp := int32(http.StatusUnauthorized)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
 		}
 		assert.Equal(t, errExp, err)
 	})
@@ -53,8 +57,10 @@ func TestIntegration_GetRoles(t *testing.T) {
 		require.Error(t, err)
 
 		errExp := roles.NewGetRolesDefault(http.StatusUnauthorized)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		codeExp := int32(http.StatusUnauthorized)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
 		}
 		assert.Equal(t, errExp, err)
 	})
diff --git a/internal/integration-tests/user/get_data_integration_test.go b/internal/integration-tests/user/get_data_integration_test.go
index 3a4ebd76..5205c65a 100644
--- a/internal/integration-tests/user/get_data_integration_test.go
+++ b/internal/integration-tests/user/get_data_integration_test.go
@@ -9,6 +9,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/client/users"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	utils "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/integration-tests/common"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -55,8 +56,10 @@ func TestIntegration_GetCurrentUser(t *testing.T) {
 		_, err = client.Users.GetCurrentUser(params, authInfo)
 
 		errExp := users.NewGetCurrentUserDefault(http.StatusUnauthorized)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		codeExp := int32(http.StatusUnauthorized)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
 		}
 		assert.Equal(t, errExp, err)
 	})
@@ -69,8 +72,11 @@ func TestIntegration_GetCurrentUser(t *testing.T) {
 		assert.Error(t, err)
 
 		errExp := users.NewGetCurrentUserDefault(401)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		msgExp := "unauthenticated for invalid credentials"
+		codeExp := int32(http.StatusUnauthorized)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
 		}
 		assert.Equal(t, errExp, err)
 	})
@@ -104,8 +110,11 @@ func TestIntegration_GetAllUsers(t *testing.T) {
 		assert.Error(t, err)
 
 		errExp := users.NewGetAllUsersDefault(401)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		msgExp := "unauthenticated for invalid credentials"
+		codeExp := int32(http.StatusUnauthorized)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
 		}
 		assert.Equal(t, errExp, err)
 	})
@@ -118,8 +127,10 @@ func TestIntegration_GetAllUsers(t *testing.T) {
 		_, err := client.Users.GetAllUsers(params, authInfo)
 
 		errExp := users.NewGetAllUsersDefault(http.StatusUnauthorized)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		codeExp := int32(http.StatusUnauthorized)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
 		}
 		assert.Equal(t, errExp, err)
 	})
diff --git a/internal/integration-tests/user/login_integration_test.go b/internal/integration-tests/user/login_integration_test.go
index 611e15fc..470be61c 100644
--- a/internal/integration-tests/user/login_integration_test.go
+++ b/internal/integration-tests/user/login_integration_test.go
@@ -61,7 +61,7 @@ func TestIntegration_Login(t *testing.T) {
 		require.Equal(t, ok, true)
 
 		wantErr := users.NewLoginUnauthorized()
-		wantErr.Payload = "Invalid login or password"
+		wantErr.Payload = "invalid login or password"
 
 		assert.Equal(t, wantErr, gotErr)
 	})
@@ -84,7 +84,7 @@ func TestIntegration_Login(t *testing.T) {
 		require.Equal(t, ok, true)
 
 		wantErr := users.NewLoginUnauthorized()
-		wantErr.Payload = "Invalid login or password"
+		wantErr.Payload = "invalid login or password"
 
 		assert.Equal(t, wantErr, gotErr)
 	})
@@ -103,8 +103,12 @@ func TestIntegration_Login(t *testing.T) {
 		require.Equal(t, ok, true)
 
 		wantErr := users.NewLoginDefault(422)
-		wantErr.Payload = &models.Error{Data: nil}
-
+		msgExp := "login in body is required"
+		codeExp := int32(602)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 }
diff --git a/internal/integration-tests/user/patch_user_integration_test.go b/internal/integration-tests/user/patch_user_integration_test.go
index 92e28b8e..bdf2b314 100644
--- a/internal/integration-tests/user/patch_user_integration_test.go
+++ b/internal/integration-tests/user/patch_user_integration_test.go
@@ -9,6 +9,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/client/users"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	utils "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/integration-tests/common"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 
 	"github.com/brianvoe/gofakeit/v6"
 	"github.com/go-openapi/strfmt"
@@ -78,8 +79,11 @@ func TestIntegration_PatchUpdate(t *testing.T) {
 		assert.Error(t, err)
 
 		errExp := users.NewPatchUserDefault(http.StatusUnauthorized)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		msgExp := "unauthenticated for invalid credentials"
+		codeExp := int32(http.StatusUnauthorized)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
 		}
 		assert.Equal(t, errExp, err)
 	})
@@ -95,8 +99,10 @@ func TestIntegration_PatchUpdate(t *testing.T) {
 		assert.Error(t, err)
 
 		errExp := users.NewPatchUserDefault(http.StatusUnauthorized)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		codeExp := int32(http.StatusUnauthorized)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
 		}
 		assert.Equal(t, errExp, err)
 	})
@@ -108,8 +114,11 @@ func TestIntegration_PatchUpdate(t *testing.T) {
 		assert.Error(t, err)
 
 		errExp := users.NewPatchUserDefault(http.StatusUnprocessableEntity)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		msgExp := "userPatch in body is required"
+		codeExp := int32(602)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
 		}
 		assert.Equal(t, errExp, err)
 	})
diff --git a/internal/integration-tests/user/refresh_integration_test.go b/internal/integration-tests/user/refresh_integration_test.go
index ea5383cf..a11a89a9 100644
--- a/internal/integration-tests/user/refresh_integration_test.go
+++ b/internal/integration-tests/user/refresh_integration_test.go
@@ -2,12 +2,14 @@ package user
 
 import (
 	"context"
+	"net/http"
 	"testing"
 	"time"
 
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/client/users"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	utils "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/integration-tests/common"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 
 	_ "github.com/jackc/pgx/v4/stdlib"
 	"github.com/stretchr/testify/assert"
@@ -79,9 +81,11 @@ func TestIntegration_Refresh(t *testing.T) {
 		require.Error(t, gotErr)
 
 		wantErr := users.NewRefreshDefault(400)
-		wantErr.Payload = &models.Error{Data: &models.ErrorData{
-			Message: "token invalid",
-		}}
+		codeExp := int32(http.StatusBadRequest)
+		wantErr.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrInvalidToken,
+		}
 		assert.Equal(t, wantErr, gotErr)
 	})
 }
diff --git a/internal/integration-tests/user/register_integration_test.go b/internal/integration-tests/user/register_integration_test.go
index a58e3c2b..a7d6d14d 100644
--- a/internal/integration-tests/user/register_integration_test.go
+++ b/internal/integration-tests/user/register_integration_test.go
@@ -8,6 +8,7 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/client/users"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
 	utils "git.epam.com/epm-lstr/epm-lstr-lc/be/internal/integration-tests/common"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 
 	"github.com/brianvoe/gofakeit/v6"
 	"github.com/go-openapi/strfmt"
@@ -57,14 +58,12 @@ func TestIntegration_RegisterUser(t *testing.T) {
 		r, err := c.Users.PostUser(params)
 		require.Error(t, err, r)
 
-		errExp := users.NewPostUserDefault(417)
-		errExp.Payload = &models.Error{
-			Data: &models.ErrorData{
-				CorrelationID: "",
-				Message:       "login is already used",
-			},
+		errExp := users.NewPostUserDefault(http.StatusExpectationFailed)
+		codeExp := int32(http.StatusExpectationFailed)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrLoginInUse,
 		}
-
 		assert.Equal(t, errExp, err)
 	})
 
@@ -120,8 +119,11 @@ func TestIntegration_RegisterUser(t *testing.T) {
 		require.Error(t, err)
 
 		errExp := users.NewPostUserDefault(422)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		msgExp := "type in body should be one of [person organization]"
+		codeExp := int32(606)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
 		}
 
 		assert.Equal(t, errExp, err)
@@ -136,24 +138,37 @@ func TestIntegration_RegisterUser(t *testing.T) {
 		require.Error(t, err)
 
 		errExp := users.NewPostUserDefault(422)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		msgExp := "login in body should be at least 3 chars long"
+		codeExp := int32(604)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
 		}
 
 		assert.Equal(t, errExp, err)
 	})
 
 	t.Run("name validation error", func(t *testing.T) {
-		empty := ""
-		data.Name = empty
+		userType = "person"
+		data = &models.UserRegister{
+			ActiveAreas: []int64{3},
+			Login:       &l,
+			Password:    &p,
+			Type:        &userType,
+			Name:        "",
+			Email:       strfmt.Email(gofakeit.Email()),
+		}
 		params.SetData(data)
 
 		_, err := c.Users.PostUser(params)
 		require.Error(t, err)
 
-		errExp := users.NewPostUserDefault(422)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		errExp := users.NewPostUserDefault(http.StatusInternalServerError)
+		codeExp := int32(http.StatusInternalServerError)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrCreateUser,
+			Details: "ent: validator failed for field \"User.name\": value is less than the required length",
 		}
 
 		assert.Equal(t, errExp, err)
@@ -161,36 +176,65 @@ func TestIntegration_RegisterUser(t *testing.T) {
 
 	t.Run("email validation error", func(t *testing.T) {
 		empty := ""
-		data.Email = strfmt.Email(empty)
+		data = &models.UserRegister{
+			ActiveAreas: []int64{3},
+			Login:       &l,
+			Password:    &p,
+			Type:        &userType,
+			Name:        gofakeit.Name(),
+			Email:       strfmt.Email(empty),
+		}
+
 		params.SetData(data)
 
 		_, err := c.Users.PostUser(params)
 		require.Error(t, err)
 
-		errExp := users.NewPostUserDefault(422)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		errExp := users.NewPostUserDefault(http.StatusInternalServerError)
+		codeExp := int32(http.StatusInternalServerError)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &messages.ErrCreateUser,
+			Details: "ent: validator failed for field \"User.email\": value is less than the required length",
 		}
 
 		assert.Equal(t, errExp, err)
 	})
 
 	t.Run("password validation error", func(t *testing.T) {
-		data.Password = nil
+		data = &models.UserRegister{
+			ActiveAreas: []int64{3},
+			Login:       &l,
+			Password:    nil,
+			Type:        &userType,
+			Name:        gofakeit.Name(),
+			Email:       strfmt.Email(gofakeit.Email()),
+		}
 		params.SetData(data)
 
 		_, err := c.Users.PostUser(params)
 		require.Error(t, err)
 
 		errExp := users.NewPostUserDefault(422)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		msgExp := "password in body is required"
+		codeExp := int32(602)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
 		}
-
 		assert.Equal(t, errExp, err)
 	})
 
 	t.Run("password validation error: length less than 3", func(t *testing.T) {
+		data = &models.UserRegister{
+			ActiveAreas: []int64{3},
+			Login:       &l,
+			Password:    &p,
+			Type:        &userType,
+			Name:        gofakeit.Name(),
+			Email:       strfmt.Email(gofakeit.Email()),
+		}
+
 		notEmpty := "22"
 		data.Password = &notEmpty
 		params.SetData(data)
@@ -199,14 +243,30 @@ func TestIntegration_RegisterUser(t *testing.T) {
 		require.Error(t, err)
 
 		errExp := users.NewPostUserDefault(422)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		msgExp := "password in body should be at least 6 chars long"
+		codeExp := int32(604)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
 		}
 
 		assert.Equal(t, errExp, err)
 	})
 
 	t.Run("type validation error: type is not person or organization", func(t *testing.T) {
+		data = &models.UserRegister{
+			ActiveAreas: []int64{3},
+			Login:       &l,
+			Password:    &p,
+			Type:        &userType,
+			// not provided in documentation, but also required
+			// todo: update documentation
+			Name: gofakeit.Name(),
+			// not provided in documentation, but also required
+			// todo: update documentation
+			Email: strfmt.Email(gofakeit.Email()),
+		}
+
 		notDefinedType := "some type"
 		data.Type = &notDefinedType
 		params.SetData(data)
@@ -215,8 +275,11 @@ func TestIntegration_RegisterUser(t *testing.T) {
 		require.Error(t, err)
 
 		errExp := users.NewPostUserDefault(422)
-		errExp.Payload = &models.Error{
-			Data: nil,
+		msgExp := "type in body should be one of [person organization]"
+		codeExp := int32(606)
+		errExp.Payload = &models.SwaggerError{
+			Code:    &codeExp,
+			Message: &msgExp,
 		}
 
 		assert.Equal(t, errExp, err)
diff --git a/internal/messages/messages.go b/internal/messages/messages.go
new file mode 100644
index 00000000..8b310a41
--- /dev/null
+++ b/internal/messages/messages.go
@@ -0,0 +1,174 @@
+package messages
+
+// Keep in mind that these messages will be used by frontend team.
+// So, if you change it, you should notify them.
+var (
+	MsgAllOk = "all ok"
+
+	// Area
+
+	ErrQueryTotalAreas = "failed to query total active areas"
+	ErrQueryAreas      = "failed to query active areas"
+
+	// Category
+
+	ErrCreateCategory       = "cant create new category"
+	ErrQueryTotalCategories = "cant get total amount of categories"
+	ErrQueryCategories      = "cant get all categories"
+	ErrGetCategory          = "failed to get category"
+	ErrDeleteCategory       = "delete category failed"
+	ErrUpdateCategory       = "cant update category"
+	MsgCategoryDeleted      = "category deleted"
+
+	// Email Confirmation
+
+	ErrEmailConfirm   = "failed to verify email confirmation token"
+	MsgEmailConfirmed = "you have successfully confirmed new email"
+
+	// Equipment Periods
+
+	ErrGetUnavailableEqStatus = "can't find unavailable equipment status dates"
+
+	// Equipment Status Names
+
+	ErrCreateEqStatus  = "can't create equipment status"
+	ErrQueryEqStatuses = "can't get equipment statuses"
+	ErrGetEqStatus     = "can't get equipment status"
+	ErrDeleteEqStatus  = "can't delete equipment status"
+
+	// Equipment Status
+
+	ErrWrongEqStatus            = "wrong new equipment status, status should be only 'not available'"
+	ErrGetEqStatusByID          = "can't find equipment status by provided id"
+	ErrOrderAndUserByEqStatusID = "can't receive order and user data during checking equipment status"
+	ErrUpdateEqStatus           = "can't update equipment status"
+
+	// Equipment
+
+	ErrCreateEquipment           = "error while creating equipment"
+	ErrMapEquipment              = "error while mapping equipment"
+	ErrGetEquipment              = "error while getting equipment"
+	ErrEquipmentNotFound         = "equipment not found"
+	ErrEquipmentArchive          = "error while archiving equipment"
+	ErrEquipmentBlock            = "error while blocking equipment"
+	ErrEquipmentUnblock          = "error while unblocking equipment"
+	ErrDeleteEquipment           = "error while deleting equipment"
+	ErrQueryTotalEquipments      = "error while getting total of all equipments"
+	ErrQueryEquipments           = "error while getting all equipments"
+	ErrUpdateEquipment           = "error while updating equipment"
+	ErrFindEquipment             = "error while finding equipment"
+	ErrEquipmentBlockForbidden   = "you don't have rights to block the equipment"
+	ErrEquipmentUnblockForbidden = "you don't have rights to unblock the equipment"
+	ErrStartDateAfterEnd         = "start date should be before end date"
+	MsgEquipmentDeleted          = "equipment deleted"
+
+	// Order Status
+
+	ErrQueryOrderHistory                 = "can't get order history"
+	ErrQueryOrderHistoryForbidden        = "you don't have rights to see this order"
+	ErrCreateOrderStatusForbidden        = "you don't have rights to add a new status"
+	ErrOrderStatusEmpty                  = "order status is empty"
+	ErrGetOrderStatus                    = "can't get order current status"
+	ErrUpdateOrderStatus                 = "can't update status"
+	ErrQueryTotalOrdersByStatus          = "can't get total count of orders by status"
+	ErrQueryOrdersByStatus               = "can't get orders by status"
+	ErrQueryTotalOrdersByPeriodAndStatus = "can't get total amount of orders by period and status"
+	ErrQueryOrdersByPeriodAndStatus      = "can't get orders by period and status"
+	ErrMapOrderStatus                    = "can't map order status name"
+	ErrQueryStatusNames                  = "can't get all status names"
+
+	// Order
+
+	ErrOrderNotFound       = "no order with such id"
+	ErrMapOrder            = "can't map order"
+	ErrQueryOrders         = "can't get orders"
+	ErrQueryTotalOrders    = "error while getting total of orders"
+	ErrUpdateOrder         = "update order failed"
+	ErrEquipmentIsNotFree  = "requested equipment is not free"
+	ErrCheckEqStatusFailed = "error while checking if equipment is available for period"
+	ErrSmallRentPeriod     = "small rent period"
+
+	// Password Reset
+
+	ErrLoginRequired          = "login is required"
+	MsgPasswordResetSuccesful = "check your email for a reset link"
+
+	// Pet Kind
+
+	ErrCreatePetKind   = "error while creating pet kind"
+	ErrGetPetKind      = "error while getting pet kind"
+	ErrPetKindNotFound = "no pet kind found"
+	ErrUpdatePetKind   = "error while updating pet kind"
+	ErrDeletePetKind   = "error while deleting pet kind"
+	MsgPetKindDeleted  = "pet kind deleted"
+
+	// Pet Size
+
+	ErrCreatePetSize        = "error while creating pet size"
+	ErrPetSizeAlreadyExists = "error while creating pet size: the name already exist"
+	ErrGetPetSize           = "error while getting pet size"
+	ErrPetSizeNotFound      = "no pet size found"
+	ErrUpdatePetSize        = "error while updating pet size"
+	ErrDeletePetSize        = "error while deleting pet size"
+	MsgPetSizeDeleted       = "pet size deleted"
+
+	// Photo
+
+	ErrCreatePhoto  = "failed to save photo"
+	ErrFileEmpty    = "File is empty"
+	ErrWrongFormat  = "Wrong file format. File should be jpg or jpeg"
+	ErrGetPhoto     = "failed to get photo"
+	ErrDeletePhoto  = "failed to delete photo"
+	MsgPhotoDeleted = "photo deleted"
+
+	// Registration Confirm
+
+	ErrRegistrationAlreadyConfirmed = "Registration is already confirmed."
+	ErrRegistrationCannotFindUser   = "Can't find this user, registration confirmation link wasn't send"
+	ErrRegistrationCannotSend       = "Can't send registration confirmation link. Please try again later"
+	ErrFailedToConfirm              = "Failed to verify confirmation token. Please try again later"
+	MsgConfirmationNotRequired      = "Confirmation link was not sent to email, sending parameter was set to false and not required"
+	MsgConfirmationSent             = "Confirmation link was sent"
+	MsgRegistrationConfirmed        = "You have successfully confirmed registration"
+
+	// Roles
+
+	ErrQueryRoles = "can't get all roles"
+
+	// Subcategory
+
+	ErrCreateSubcategory   = "failed to create new subcategory"
+	ErrMapSubcategory      = "failed to map new subcategory"
+	ErrQuerySCatByCategory = "failed to list subcategories by category id"
+	ErrGetSubcategory      = "failed to get subcategory"
+	ErrDeleteSubcategory   = "failed to delete subcategory"
+	ErrUpdateSubcategory   = "failed to update subcategory"
+	MsgSubcategoryDeleted  = "subcategory deleted"
+
+	// User
+
+	ErrInvalidLoginOrPass   = "invalid login or password"
+	ErrLoginInUse           = "login is already used"
+	ErrCreateUser           = "failed to create user"
+	ErrInvalidToken         = "token is invalid"
+	ErrTokenRefresh         = "error while refreshing token"
+	ErrMapUser              = "map user error"
+	ErrUserNotFound         = "can't find user by id"
+	ErrUpdateUser           = "can't update user"
+	ErrRoleRequired         = "role id is required"
+	ErrSetUserRole          = "set user role error"
+	ErrQueryTotalUsers      = "failed get user total amount"
+	ErrQueryUsers           = "failed to get user list"
+	ErrDeleteUser           = "can't delete user"
+	ErrDeleteUserNotRO      = "user must be readonly for deletion"
+	ErrUserPasswordChange   = "error while changing password"
+	ErrWrongPassword        = "wrong password"
+	ErrPasswordsAreSame     = "old and new passwords are the same"
+	ErrPasswordPatchEmpty   = "password patch is empty"
+	ErrUpdateROAccess       = "error while updating readonly access"
+	ErrChangeEmail          = "error while changing email"
+	ErrEmailPatchEmpty      = "email patch is empty"
+	ErrNewEmailConfirmation = "can't send link for confirmation new email"
+	MsgLogoutSuccessful     = "successfully logged out"
+	MsgRoleAssigned         = "role assigned"
+)
diff --git a/internal/middlewares/access_manager.go b/internal/middlewares/access_manager.go
index 78384ec3..b0268c9a 100644
--- a/internal/middlewares/access_manager.go
+++ b/internal/middlewares/access_manager.go
@@ -77,12 +77,12 @@ func allRoleVariation(roles []Role) []Role {
 	variations := []bool{false, true}
 
 	for _, role := range roles {
-		for _, isRegistrationConfirmed := range variations {
+		for _, IsRegistrationConfirmed := range variations {
 			for _, isPersonalDataConfirmed := range variations {
 				for _, isReadonly := range variations {
 					res = append(res, Role{
 						Slug:                    role.Slug,
-						IsRegistrationConfirmed: isRegistrationConfirmed,
+						IsRegistrationConfirmed: IsRegistrationConfirmed,
 						IsPersonalDataConfirmed: isPersonalDataConfirmed,
 						IsReadonly:              isReadonly,
 					})
@@ -199,7 +199,7 @@ func (a *blackListAccessManager) VerifyAccess(role Role, method, path string) er
 	}
 	allowedPaths, ok := a.accessMap[role][method]
 	if !ok {
-		return openApiErrors.New(http.StatusForbidden, models.SwaggerErrorMessageUserIsNotAuthorized)
+		return openApiErrors.New(http.StatusForbidden, "user is not authorized")
 	}
 	for _, allowedPath := range allowedPaths {
 		if allowedPath.isMatch(path) {
@@ -207,15 +207,15 @@ func (a *blackListAccessManager) VerifyAccess(role Role, method, path string) er
 		}
 	}
 	if !role.IsRegistrationConfirmed {
-		return openApiErrors.New(http.StatusForbidden, models.SwaggerErrorMessageUserHasNoConfirmedEmail)
+		return openApiErrors.New(http.StatusForbidden, "user has no confirmed email")
 	}
-	return openApiErrors.New(http.StatusForbidden, models.SwaggerErrorMessageUserIsNotAuthorized)
+	return openApiErrors.New(http.StatusForbidden, "user is not authorized")
 }
 
 func (a *blackListAccessManager) Authorize(r *http.Request, auth interface{}) error {
 	principal, ok := auth.(*models.Principal)
 	if !ok {
-		return openApiErrors.New(http.StatusForbidden, models.SwaggerErrorMessageUserIsNotAuthorized)
+		return openApiErrors.New(http.StatusForbidden, "user is not authorized")
 	}
 
 	role := Role{
diff --git a/internal/middlewares/api_key_auth.go b/internal/middlewares/api_key_auth.go
index 4ba67317..4523c773 100644
--- a/internal/middlewares/api_key_auth.go
+++ b/internal/middlewares/api_key_auth.go
@@ -10,13 +10,14 @@ import (
 
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/ent"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/messages"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/services"
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
 )
 
 func TokenInvalidError() error {
 	// make sure that the error message is exactly as the one in the #/definitions/SwaggerError object.
-	return errors.New(http.StatusUnauthorized, "Token is invalid")
+	return errors.New(http.StatusUnauthorized, messages.ErrInvalidToken)
 }
 
 func APIKeyAuthFunc(key interface{}, userRepository domain.UserRepository) func(context.Context, string) (context.Context, interface{}, error) {
diff --git a/internal/middlewares/tx.go b/internal/middlewares/tx.go
index 895086a7..6a88c6da 100644
--- a/internal/middlewares/tx.go
+++ b/internal/middlewares/tx.go
@@ -2,12 +2,11 @@ package middlewares
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
 	"net/http"
 
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/ent"
-	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/utils"
 )
 
 type contextKey string
@@ -34,13 +33,7 @@ func Tx(cln *ent.Client) func(next http.Handler) http.Handler {
 			ctx := r.Context()
 			tx, err = cln.Tx(ctx)
 			if err != nil {
-				writeResponse(w, http.StatusInternalServerError, &models.Error{
-					Data: &models.ErrorData{
-						// TODO: add correlation id
-						CorrelationID: "",
-						Message:       "Error initiating transaction",
-					},
-				})
+				utils.WriteErrorResponse(w, http.StatusInternalServerError, "Error initiating transaction")
 				return
 			}
 			defer func() {
@@ -62,15 +55,3 @@ func Tx(cln *ent.Client) func(next http.Handler) http.Handler {
 		})
 	}
 }
-
-func writeResponse(w http.ResponseWriter, code int, v interface{}) {
-	w.Header().Set("Content-Type", "application/json")
-	b, err := json.Marshal(v)
-	if err != nil {
-		w.WriteHeader(http.StatusInternalServerError)
-		w.Write([]byte(`{"data":{"message":"Internal server error"}}`))
-		return
-	}
-	w.WriteHeader(code)
-	w.Write(b)
-}
diff --git a/internal/repositories/equipment.go b/internal/repositories/equipment.go
index 708815c9..b19fa7fd 100644
--- a/internal/repositories/equipment.go
+++ b/internal/repositories/equipment.go
@@ -510,11 +510,6 @@ func (r *equipmentRepository) BlockEquipment(
 		return err
 	}
 
-	start, end, err := checkDates(&startDate, &endDate)
-	if err != nil {
-		return err
-	}
-
 	// Set a new EquipmentStatusName for current Equipment
 	_, err = eqToBlock.Update().SetCurrentStatus(eqStatusNotAvailable).Save(ctx)
 	if err != nil {
@@ -524,8 +519,8 @@ func (r *equipmentRepository) BlockEquipment(
 	// Create a new EquipmentStatus and set startDate, endDate, Equipment and EquipmentStatusName
 	_, err = tx.EquipmentStatus.Create().
 		SetCreatedAt(time.Now()).
-		SetEndDate(*end).
-		SetStartDate(*start).
+		SetEndDate(startDate).
+		SetStartDate(endDate).
 		SetEquipments(eqToBlock).
 		SetEquipmentStatusName(eqStatusNotAvailable).
 		SetUpdatedAt(time.Now()).
@@ -545,8 +540,8 @@ func (r *equipmentRepository) BlockEquipment(
 
 	// Find all Orders which have OrderStatusName booked and start from startDate and later
 	orderIDs, err := eqToBlock.QueryOrder().
-		Where(order.RentStartGTE(*start), order.RentStartLTE(*end)). // rentStart must be in range of startDate..endDate
-		Where(order.RentEndGTE(*start)).                             // rentEnd must be equal or greater than startDate
+		Where(order.RentStartGTE(startDate), order.RentStartLTE(endDate)). // rentStart must be in range of startDate..endDate
+		Where(order.RentEndGTE(startDate)).                                // rentEnd must be equal or greater than startDate
 		Where(order.HasCurrentStatusWith(orderstatusname.StatusIn(
 			domain.OrderStatusPrepared,
 			domain.OrderStatusApproved))).
@@ -637,17 +632,6 @@ func (r *equipmentRepository) UnblockEquipment(ctx context.Context, id int) erro
 	return err
 }
 
-func checkDates(start *time.Time, end *time.Time) (*time.Time, *time.Time, error) {
-	startDate := time.Time(*start)
-	endDate := time.Time(*end)
-
-	if startDate.After(endDate) {
-		return nil, nil, errors.New("start date should be before end date")
-	}
-
-	return &startDate, &endDate, nil
-}
-
 // Set EquipmentStatus EndDate back in time to give access for the unblocked equipment again
 func truncateHours(date *time.Time) time.Time {
 	extraHour := 1
diff --git a/internal/repositories/equipment_test.go b/internal/repositories/equipment_test.go
index c5aba342..2dd32f16 100644
--- a/internal/repositories/equipment_test.go
+++ b/internal/repositories/equipment_test.go
@@ -658,56 +658,6 @@ func (s *EquipmentSuite) TestEquipmentRepository_UnblockEquipment() {
 	require.NoError(t, tx.Commit())
 }
 
-func Test_checkDates(t *testing.T) {
-	start := time.Now()
-	end := time.Now().Add(time.Hour * 24)
-	var blankTime time.Time
-	type args struct {
-		start *time.Time
-		end   *time.Time
-	}
-	tests := []struct {
-		name    string
-		args    args
-		want    *time.Time
-		want1   *time.Time
-		wantErr bool
-	}{
-		{
-			name:    "When correct time",
-			args:    args{start: &start, end: &end},
-			want:    &start,
-			want1:   &end,
-			wantErr: false,
-		},
-		{
-			name:    "When end date becomes earlier thar start date",
-			args:    args{start: &end, end: &start},
-			want:    nil,
-			want1:   nil,
-			wantErr: true,
-		},
-		{
-			name:    "When default time",
-			args:    args{start: &blankTime, end: &blankTime},
-			want:    &blankTime,
-			want1:   &blankTime,
-			wantErr: false,
-		},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			got, got1, err := checkDates(tt.args.start, tt.args.end)
-			require.Equal(t, tt.want, got)
-			require.Equal(t, tt.want1, got1)
-			if (err != nil) != tt.wantErr {
-				t.Errorf("checkDates() error = %v, wantErr %v", err, tt.wantErr)
-				return
-			}
-		})
-	}
-}
-
 func Test_truncateHours(t *testing.T) {
 	date := time.Now()
 	type args struct {
diff --git a/internal/repositories/order.go b/internal/repositories/order.go
index 26f74f0e..6185360d 100644
--- a/internal/repositories/order.go
+++ b/internal/repositories/order.go
@@ -22,11 +22,11 @@ import (
 	"git.epam.com/epm-lstr/epm-lstr-lc/be/pkg/domain"
 )
 
-type OrderAccessDenied struct {
+type OrderValidationError struct {
 	Err error
 }
 
-func (r OrderAccessDenied) Error() string {
+func (r OrderValidationError) Error() string {
 	return r.Err.Error()
 }
 
@@ -46,18 +46,9 @@ func getDates(start *strfmt.DateTime, end *strfmt.DateTime, maxSeconds int) (*ti
 	rentStart := time.Time(*start)
 	rentEnd := time.Time(*end)
 
-	if rentStart.After(rentEnd) {
-		return nil, nil, errors.New("start date should be before end date")
-	}
-
-	diff := rentEnd.Sub(rentStart)
-	days := diff.Hours() / 24
-	if days < 1 {
-		return nil, nil, errors.New("small rent period")
-	}
-
-	if int(diff.Seconds()) > maxSeconds {
-		return nil, nil, errors.New("too big reservation period")
+	if int(rentEnd.Sub(rentStart).Seconds()) > maxSeconds {
+		// This kind of validation cannot be performed on handler's layer
+		return nil, nil, OrderValidationError{Err: errors.New("too big reservation period")}
 	}
 
 	return &rentStart, &rentEnd, nil
@@ -65,7 +56,8 @@ func getDates(start *strfmt.DateTime, end *strfmt.DateTime, maxSeconds int) (*ti
 
 func getQuantity(quantity int, maxQuantity int) (*int, error) {
 	if quantity > maxQuantity {
-		return nil, fmt.Errorf("quantity limit exceeded: %d allowed", maxQuantity)
+		// This kind of validation cannot be performed on handler's layer
+		return nil, OrderValidationError{Err: fmt.Errorf("quantity limit exceeded: %d allowed", maxQuantity)}
 	}
 
 	return &quantity, nil
@@ -224,7 +216,7 @@ func (r *orderRepository) Update(ctx context.Context, id int, data *models.Order
 	}
 
 	if owner.ID != userId {
-		return nil, OrderAccessDenied{Err: errors.New("permission denied")}
+		return nil, OrderValidationError{Err: errors.New("permission denied")}
 	}
 
 	equipment, err := foundOrder.QueryEquipments().First(ctx)
diff --git a/internal/utils/error_response.go b/internal/utils/error_response.go
new file mode 100644
index 00000000..a4a2c42a
--- /dev/null
+++ b/internal/utils/error_response.go
@@ -0,0 +1,24 @@
+package utils
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"git.epam.com/epm-lstr/epm-lstr-lc/be/internal/generated/swagger/models"
+)
+
+func WriteErrorResponse(w http.ResponseWriter, code int32, message string) {
+	w.Header().Set("Content-Type", "application/json")
+	e := models.SwaggerError{
+		Code:    &code,
+		Message: &message,
+	}
+	b, err := json.Marshal(e)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte(`{"code":500,"message":"Unexpected error"}`))
+		return
+	}
+	w.WriteHeader(int(code))
+	w.Write(b)
+}
diff --git a/swagger.yaml b/swagger.yaml
index 4cdbe1ca..10640968 100644
--- a/swagger.yaml
+++ b/swagger.yaml
@@ -32,7 +32,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /v1/login:
     post:
       description: 'Returns token for authorized User'
@@ -60,7 +60,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /v1/logout:
     post:
       description: 'Logout user'
@@ -84,11 +84,11 @@ paths:
         404:
           description: Refresh token not found.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /v1/refresh:
     post:
       description: 'Returns new token pair for an authorized User'
@@ -113,11 +113,11 @@ paths:
         404:
           description: Refresh token not found.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /v1/users:
     get:
       parameters:
@@ -169,7 +169,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     post:
       summary: Register a new user.
       tags:
@@ -190,7 +190,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /v1/users/me:
     get:
       summary: Get the current user data.
@@ -207,7 +207,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     patch:
       summary: Edit selected fields of the current user.
       security:
@@ -230,7 +230,7 @@ paths:
         default:
           description: Unexpected error
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     delete:
       summary: Delete the current user.
       security:
@@ -244,7 +244,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /v1/users/me/password:
     patch:
       summary: Change the current user password.
@@ -268,15 +268,15 @@ paths:
         401:
           description: Unauthorized
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
         403:
           description: Wrong old password
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
         default:
           description: Unexpected error
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /v1/users/me/email:
     patch:
       summary: Change the current email.
@@ -300,11 +300,11 @@ paths:
         401:
           description: Unauthorized
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /v1/email_confirm/{token}:
     get:
       summary: Verify email confirmation token.
@@ -324,7 +324,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /management/users/{userId}:
     parameters:
       - name: userId
@@ -347,7 +347,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /v1/roles:
     get:
       summary: List all roles.
@@ -364,7 +364,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /v1/management/users/{userId}/role:
     parameters:
       - name: userId
@@ -396,7 +396,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
 
   /v1/users/{userId}:
     parameters:
@@ -429,7 +429,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     delete:
       consumes:
         - application/json
@@ -445,11 +445,11 @@ paths:
         404:
           description: User not found
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
 
   /v1/users/{userId}/readonly-access:
     put:
@@ -481,23 +481,23 @@ paths:
         400:
           description: Bad request
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
         401:
           description: Unauthorized
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
         403:
           description: Forbidden
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
         404:
           description: User not found
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
 
   /equipmentstatus/repaired/{equipmentstatusId}:
     parameters:
@@ -528,7 +528,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     put:
       summary: Change equipment status on unavailable with start/end dates by id.
       security:
@@ -551,7 +551,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     get:
       summary: Check that equipment status has orders on provided dates.
       security:
@@ -574,7 +574,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     patch:
       summary: Change repaired equipment status dates by id.
       security:
@@ -597,7 +597,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /equipment/status_names:
     post:
       summary: Creating a new equipment status.
@@ -621,7 +621,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     get:
       summary: List all statuses.
       security:
@@ -637,7 +637,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /equipment/statuses/{statusId}:
     parameters:
       - name: statusId
@@ -660,7 +660,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     delete:
       summary: Delete status by id
       security:
@@ -676,7 +676,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /equipment/categories:
     get:
       parameters:
@@ -730,7 +730,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     post:
       summary: Create a new Category.
       security:
@@ -753,7 +753,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /equipment/unavailability_periods/{equipmentId}:
     parameters:
       - name: equipmentId
@@ -776,7 +776,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
         404:
           schema:
             type: string
@@ -803,7 +803,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     delete:
       summary: Delete category of equipment from db by id.
       security:
@@ -819,7 +819,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     put:
       summary: Edit equipment category by id.
       security:
@@ -841,7 +841,7 @@ paths:
         default:
           description: Unexpected error
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /equipment/categories/{categoryId}/subcategories:
     parameters:
       - name: categoryId
@@ -864,7 +864,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     post:
       summary: Create a new Subcategory.
       security:
@@ -887,7 +887,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /equipment/categories/subcategories/{subcategoryId}:
     parameters:
       - name: subcategoryId
@@ -910,7 +910,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     delete:
       summary: Delete subcategory of equipment from db by id.
       security:
@@ -926,7 +926,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     put:
       summary: Edit equipment subcategory by id.
       security:
@@ -948,7 +948,7 @@ paths:
         default:
           description: Unexpected error
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /equipment/photos:
     post:
       summary: Upload a new equipment photo
@@ -973,11 +973,11 @@ paths:
         400:
           description: Bad request
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /equipment/photos/{photoId}:
     parameters:
       - name: photoId
@@ -1003,7 +1003,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     delete:
       summary: Delete photo by id
       security:
@@ -1019,7 +1019,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /equipment/photos/{photoId}/download:
     parameters:
       - name: photoId
@@ -1045,7 +1045,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /v1/orders:
     get:
       tags:
@@ -1110,7 +1110,7 @@ paths:
         default:
           description: 'Unexpected error'
           schema:
-            $ref: '#/definitions/Error'
+            $ref: '#/definitions/SwaggerError'
     post:
       tags:
         - Orders
@@ -1127,7 +1127,7 @@ paths:
         default:
           description: 'Unexpected error'
           schema:
-            $ref: '#/definitions/Error'
+            $ref: '#/definitions/SwaggerError'
       parameters:
         - name: data
           in: body
@@ -1163,7 +1163,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /v1/order_statuses/{orderId}:
     get:
       summary: Get full order status history.
@@ -1190,7 +1190,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /v1/order_statuses/:
     post:
       summary: Add new order status to order status history.
@@ -1214,7 +1214,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: '#/definitions/Error'
+            $ref: '#/definitions/SwaggerError'
   /v1/orders/status/{status}:
     get:
       summary: Get orders by status.
@@ -1274,7 +1274,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: '#/definitions/Error'
+            $ref: '#/definitions/SwaggerError'
   /v1/orders/from={fromDate}&to={toDate}&status={statusName}:
     get:
       summary: Get orders by date and status.
@@ -1343,7 +1343,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: '#/definitions/Error'
+            $ref: '#/definitions/SwaggerError'
   /v1/status_names:
     get:
       summary: Get all status names.
@@ -1360,7 +1360,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: '#/definitions/Error'
+            $ref: '#/definitions/SwaggerError'
   /v1/active_areas:
     get:
       parameters:
@@ -1408,7 +1408,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /equipment:
     post:
       summary: Register a new equipment
@@ -1434,7 +1434,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     get:
       summary: Get all equipment
       security:
@@ -1482,7 +1482,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /equipment/{equipmentId}:
     parameters:
       - name: equipmentId
@@ -1505,7 +1505,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     delete:
       summary: Delete equipment by id
       security:
@@ -1521,7 +1521,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     put:
       summary: Edit equipment by id
       security:
@@ -1544,7 +1544,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /equipment/achive/{equipmentId}/:
     parameters:
       - name: equipmentId
@@ -1565,11 +1565,11 @@ paths:
           404:
             description: Equipment not found
             schema:
-              $ref: "#/definitions/Error"
+              $ref: "#/definitions/SwaggerError"
           default:
             description: Unexpected error.
             schema:
-                $ref: "#/definitions/Error"
+                $ref: "#/definitions/SwaggerError"
   /equipment/{equipmentId}/blocking:
     parameters:
       - name: equipmentId
@@ -1597,11 +1597,11 @@ paths:
           404:
             description: Equipment not found
             schema:
-              $ref: "#/definitions/Error"
+              $ref: "#/definitions/SwaggerError"
           default:
             description: Unexpected error.
             schema:
-                $ref: "#/definitions/Error"
+                $ref: "#/definitions/SwaggerError"
   /equipment/{equipmentId}/unblocking:
     parameters:
       - name: equipmentId
@@ -1622,11 +1622,11 @@ paths:
           404:
             description: Equipment not found
             schema:
-              $ref: "#/definitions/Error"
+              $ref: "#/definitions/SwaggerError"
           default:
             description: Unexpected error.
             schema:
-                $ref: "#/definitions/Error"
+                $ref: "#/definitions/SwaggerError"
   /equipment/search:
     post:
       summary: Equipment filtered list
@@ -1681,7 +1681,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /pet_size:
     post:
       summary: Register a new pet size
@@ -1707,7 +1707,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     get:
       summary: Get all pet size
       security:
@@ -1723,7 +1723,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /pet_size/{petSizeId}:
     parameters:
       - name: petSizeId
@@ -1746,7 +1746,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     delete:
       summary: Delete pet size by id
       security:
@@ -1762,7 +1762,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     put:
       summary: Edit pet size by id
       security:
@@ -1785,7 +1785,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
 
   /password_reset/:
     post:
@@ -1807,7 +1807,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
 
   /password_reset/{token}:
     get:
@@ -1828,7 +1828,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
 
   /pet_kind:
     get:
@@ -1846,7 +1846,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     post:
       summary: Register a new pet kind
       security:
@@ -1871,7 +1871,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /pet_kind/{petKindId}:
     parameters:
       - name: petKindId
@@ -1894,7 +1894,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     delete:
       summary: Delete pet kind by id
       security:
@@ -1910,7 +1910,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
     put:
       summary: Edit pet kind by id
       security:
@@ -1933,7 +1933,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
 
   /registration_confirm/:
     post:
@@ -1955,7 +1955,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
 
   /registration_confirm/{token}:
     get:
@@ -1976,7 +1976,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
   /management/orders:
     get:
       summary: Get all orders
@@ -2048,7 +2048,7 @@ paths:
         default:
           description: Unexpected error.
           schema:
-            $ref: "#/definitions/Error"
+            $ref: "#/definitions/SwaggerError"
 
 definitions:
   principal:
@@ -2072,16 +2072,11 @@ definitions:
     properties:
         code:
             type: integer
-            enum:
-              - 401
-              - 403
             format: int32
         message:
             type: string
-            enum:
-              - Token is invalid
-              - User is not authorized
-              - User has no confirmed email
+        details:
+            type: string
   PetKind:
     type: object
     required:
@@ -2089,18 +2084,6 @@ definitions:
     properties:
       name:
         type: string
-  Error:
-    type: object
-    required:
-      - data
-    properties:
-      data:
-        type: object
-        properties:
-          correlationId:
-            type: string
-          message:
-            type: string
 
   ListOfPetKinds:
     type: array