diff --git a/users/bolt/bolt.go b/users/bolt/bolt.go
index 915bffb..aa925fc 100644
--- a/users/bolt/bolt.go
+++ b/users/bolt/bolt.go
@@ -70,16 +70,17 @@ func (db *DB) UpdateUser(ctx context.Context, u users.User) (users.User, error)
 }
 
 // DeleteUser deletes a user record from the database.
-func (db *DB) DeleteUser(ctx context.Context, id string) (users.User, error) {
+func (db *DB) DeleteUser(ctx context.Context, id string) error {
 	prev, err := internal.GetSnap([]byte(id), db._db)
 	if err != nil {
-		return nil, err
+		return err
 	}
 
 	e, err := internal.NewDeleteEvent(prev.User, prev.Version)
 	if err != nil {
-		return nil, errors.Wrap(err, "NewDeleteEvent")
+		return errors.Wrap(err, "NewDeleteEvent")
 	}
 
-	return e.Apply(ctx, db._db)
+	_, err = e.Apply(ctx, db._db)
+	return err
 }
diff --git a/users/bolt/bolt_test.go b/users/bolt/bolt_test.go
index 073dc7c..6d39640 100644
--- a/users/bolt/bolt_test.go
+++ b/users/bolt/bolt_test.go
@@ -53,7 +53,7 @@ func TestCRUD(t *testing.T) {
 	test.Assert(t, u.GetID() == _u.GetID(), "ids should be equal")
 	test.Assert(t, u.GetName() == _u.GetName(), "names should be equal")
 	// delete
-	_, err = db.DeleteUser(ctx, u.GetID())
+	err = db.DeleteUser(ctx, u.GetID())
 	test.OK(t, err)
 	_u, err = db.GetUser(ctx, u.GetID())
 	test.OK(t, err)
diff --git a/users/bolt/go.mod b/users/bolt/go.mod
index b690880..f1dfa52 100644
--- a/users/bolt/go.mod
+++ b/users/bolt/go.mod
@@ -6,7 +6,7 @@ require (
 	github.com/gogo/protobuf v1.1.1 // indirect
 	github.com/justanotherorganization/justanotherbotkit/internal v0.0.1
 	github.com/justanotherorganization/justanotherbotkit/proto v0.0.1
-	github.com/justanotherorganization/justanotherbotkit/users v0.0.1
+	github.com/justanotherorganization/justanotherbotkit/users v0.0.2rc1
 	github.com/pkg/errors v0.8.0
 	go.etcd.io/bbolt v1.3.0
 	golang.org/x/sys v0.0.0-20181022134430-8a28ead16f52 // indirect
diff --git a/users/bolt/go.sum b/users/bolt/go.sum
index 614f507..a63147c 100644
--- a/users/bolt/go.sum
+++ b/users/bolt/go.sum
@@ -8,8 +8,6 @@ github.com/justanotherorganization/justanotherbotkit/internal v0.0.1 h1:2odRvxW1
 github.com/justanotherorganization/justanotherbotkit/internal v0.0.1/go.mod h1:Ky6Plt9xEtoSkl64huLSkq0lq1xYKBxI58Wb45mucV8=
 github.com/justanotherorganization/justanotherbotkit/proto v0.0.1 h1:N2hHF03EYoOfKXFlU4Sx97laA1fGu5K7K0ZjgbaGjF8=
 github.com/justanotherorganization/justanotherbotkit/proto v0.0.1/go.mod h1:r2hwUKNIK21pZ+e1KuoNWCRDJIpotmDrwS02cMKZu6c=
-github.com/justanotherorganization/justanotherbotkit/users v0.0.1 h1:g96VVlYIYV5kRYfG2eLBQa5Cptg1WaKu2Xv8eftOz6M=
-github.com/justanotherorganization/justanotherbotkit/users v0.0.1/go.mod h1:pSY/4vMnSHd4qjLQzLFe3WyGhpVYhNibLQuZTjkIpE4=
 github.com/pkg/errors v0.8.0 h1:WdK/asTD0HN+q6hsWO3/vpuAkAr+tw6aNJNDFFf0+qw=
 github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 go.etcd.io/bbolt v1.3.0 h1:oY10fI923Q5pVCVt1GBTZMn8LHo5M+RCInFpeMnV4QI=
diff --git a/users/db.go b/users/db.go
index 49dd7c1..6f94bef 100644
--- a/users/db.go
+++ b/users/db.go
@@ -12,6 +12,6 @@ type (
 		// UpdateUser updates a user record in the database.
 		UpdateUser(ctx context.Context, u User) (User, error)
 		// DeleteUser deletes a user record from the database.
-		DeleteUser(ctx context.Context, id string) (User, error)
+		DeleteUser(ctx context.Context, id string) error
 	}
 )
diff --git a/users/mock/db.go b/users/mock/db.go
new file mode 100644
index 0000000..7356359
--- /dev/null
+++ b/users/mock/db.go
@@ -0,0 +1,60 @@
+package mock // import "github.com/justanotherorganization/justanotherbotkit/users/mock"
+
+import (
+	"context"
+	"sync"
+
+	"github.com/justanotherorganization/justanotherbotkit/users"
+)
+
+// DB is a mock database.
+type DB struct {
+	sync.RWMutex
+	m map[string]users.User
+}
+
+// Static type checking
+var _ users.DB = &DB{}
+
+// New returns a new in-memory user database.
+func New() (db *DB) {
+	db = new(DB)
+	db.m = make(map[string]users.User)
+	return db
+}
+
+// CreateUser creates a new user and saves it in memory.
+func (db *DB) CreateUser(_ context.Context, u users.User) (users.User, error) {
+	db.Lock()
+	defer db.Unlock()
+	db.m[u.GetID()] = u
+	return u, nil
+}
+
+// GetUser gets a user from the database using the ID.
+func (db *DB) GetUser(_ context.Context, id string) (users.User, error) {
+	db.RLock()
+	defer db.RUnlock()
+	u := db.m[id]
+	return u, nil
+}
+
+// UpdateUser udpates a user record in memory.
+func (db *DB) UpdateUser(_ context.Context, u users.User) (users.User, error) {
+	db.Lock()
+	defer db.Unlock()
+	db.m[u.GetID()] = u
+	return u, nil
+}
+
+// DeleteUser deletes a user record from memory.
+func (db *DB) DeleteUser(_ context.Context, id string) error {
+	db.Lock()
+	defer db.Unlock()
+	_, ok := db.m[id]
+	if ok {
+		delete(db.m, id)
+	}
+
+	return nil
+}
diff --git a/users/mock/db_test.go b/users/mock/db_test.go
new file mode 100644
index 0000000..c581238
--- /dev/null
+++ b/users/mock/db_test.go
@@ -0,0 +1,50 @@
+package mock_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/gofrs/uuid"
+	"github.com/justanotherorganization/justanotherbotkit/internal/test"
+	"github.com/justanotherorganization/justanotherbotkit/proto"
+	. "github.com/justanotherorganization/justanotherbotkit/users/mock"
+)
+
+func newTestUser(tb testing.TB) *pb.BaseUser {
+	uid, err := uuid.NewV4()
+	test.OK(tb, err)
+	id := uid.String()
+
+	return &pb.BaseUser{
+		ID:   id,
+		Name: id,
+	}
+}
+
+func TestCRUD(t *testing.T) {
+	ctx := context.Background()
+	db := New()
+	// create
+	u := newTestUser(t)
+	_u, err := db.CreateUser(ctx, u)
+	test.OK(t, err)
+	test.Assert(t, u.GetID() == _u.GetID(), "ids should be equal")
+	test.Assert(t, u.GetName() == _u.GetName(), "names should be equal")
+	// retrieve
+	_u, err = db.GetUser(ctx, u.GetID())
+	test.OK(t, err)
+	test.Assert(t, u.GetID() == _u.GetID(), "ids should be equal")
+	test.Assert(t, u.GetName() == _u.GetName(), "names should be equal")
+	// update
+	u.Name = "test"
+	_u, err = db.UpdateUser(ctx, u)
+	test.OK(t, err)
+	test.Assert(t, u.GetID() == _u.GetID(), "ids should be equal")
+	test.Assert(t, u.GetName() == _u.GetName(), "names should be equal")
+	// delete
+	err = db.DeleteUser(ctx, u.GetID())
+	test.OK(t, err)
+	_u, err = db.GetUser(ctx, u.GetID())
+	test.OK(t, err)
+	test.Assert(t, _u == nil, "user should not exist")
+}
diff --git a/users/mock/go.mod b/users/mock/go.mod
new file mode 100644
index 0000000..9d71678
--- /dev/null
+++ b/users/mock/go.mod
@@ -0,0 +1,9 @@
+module github.com/justanotherorganization/justanotherbotkit/users/mock
+
+require (
+	github.com/gofrs/uuid v3.1.0+incompatible
+	github.com/gogo/protobuf v1.1.1 // indirect
+	github.com/justanotherorganization/justanotherbotkit/internal v0.0.1
+	github.com/justanotherorganization/justanotherbotkit/proto v0.0.1
+	github.com/justanotherorganization/justanotherbotkit/users v0.0.2rc1
+)
diff --git a/users/mock/go.sum b/users/mock/go.sum
new file mode 100644
index 0000000..e5ba9e9
--- /dev/null
+++ b/users/mock/go.sum
@@ -0,0 +1,8 @@
+github.com/gofrs/uuid v3.1.0+incompatible h1:q2rtkjaKT4YEr6E1kamy0Ha4RtepWlQBedyHx0uzKwA=
+github.com/gofrs/uuid v3.1.0+incompatible/go.mod h1:b2aQJv3Z4Fp6yNu3cdSllBxTCLRxnplIgP/c0N/04lM=
+github.com/gogo/protobuf v1.1.1 h1:72R+M5VuhED/KujmZVcIquuo8mBgX4oVda//DQb3PXo=
+github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
+github.com/justanotherorganization/justanotherbotkit/internal v0.0.1 h1:2odRvxW138OANcE7Oj1kBK9FiJorwKfV4nFsGTcQAB8=
+github.com/justanotherorganization/justanotherbotkit/internal v0.0.1/go.mod h1:Ky6Plt9xEtoSkl64huLSkq0lq1xYKBxI58Wb45mucV8=
+github.com/justanotherorganization/justanotherbotkit/proto v0.0.1 h1:N2hHF03EYoOfKXFlU4Sx97laA1fGu5K7K0ZjgbaGjF8=
+github.com/justanotherorganization/justanotherbotkit/proto v0.0.1/go.mod h1:r2hwUKNIK21pZ+e1KuoNWCRDJIpotmDrwS02cMKZu6c=