diff --git a/app/api/entities/specs/denormalization.spec.ts b/app/api/entities/specs/denormalization.spec.ts
index 183ded5951..87faa11a74 100644
--- a/app/api/entities/specs/denormalization.spec.ts
+++ b/app/api/entities/specs/denormalization.spec.ts
@@ -42,6 +42,7 @@ describe('Denormalize relationships', () => {
   describe('title and basic property (text)', () => {
     it('should update denormalized title and icon', async () => {
       const fixtures: DBFixture = {
+        relationtypes: [factory.relationType('rel1')],
         templates: [
           factory.template('templateA', [
             factory.relationshipProp('relationship', 'templateB', 'text'),
@@ -232,6 +233,7 @@ describe('Denormalize relationships', () => {
 
   describe('when the relationship property has no content', () => {
     const fixtures: DBFixture = {
+      relationtypes: [factory.relationType('rel1')],
       templates: [
         factory.template('templateA', [
           factory.relationshipProp('relationship', '', { content: '' }),
@@ -289,6 +291,7 @@ describe('Denormalize relationships', () => {
     beforeEach(async () => {
       jest.spyOn(translations, 'updateContext').mockImplementation(async () => 'ok');
       const fixtures: DBFixture = {
+        relationtypes: [factory.relationType('rel1')],
         templates: [
           factory.template('templateA', [
             factory.inherit('relationship', 'templateB', 'multiselect'),
@@ -383,6 +386,7 @@ describe('Denormalize relationships', () => {
   describe('inherited relationship', () => {
     beforeEach(async () => {
       const fixtures: DBFixture = {
+        relationtypes: [factory.relationType('rel1')],
         templates: [
           factory.template('templateA', [
             factory.inherit('relationship', 'templateB', 'relationshipB'),
@@ -444,6 +448,7 @@ describe('Denormalize relationships', () => {
     beforeEach(async () => {
       await load(
         {
+          relationtypes: [factory.relationType('rel1')],
           templates: [
             factory.template('templateA', [
               factory.inherit('relationshipA', 'templateB', 'relationshipB'),
diff --git a/app/api/entities/specs/fixtures.js b/app/api/entities/specs/fixtures.js
index 5bba0346f3..89908daeb2 100644
--- a/app/api/entities/specs/fixtures.js
+++ b/app/api/entities/specs/fixtures.js
@@ -683,6 +683,12 @@ export default {
       name: 'templateForGetWithRelationships',
     },
   ],
+  relationtypes: [
+    { _id: relationType1 },
+    { _id: relationType2 },
+    { _id: relationType3 },
+    { _id: relationType4 },
+  ],
   connections: [
     { _id: referenceId, entity: 'shared', template: null, hub: hub1, entityData: {} },
     { _id: db.id(), entity: 'shared2', template: relationType1, hub: hub1, entityData: {} },
diff --git a/app/api/relationships/relationships.js b/app/api/relationships/relationships.js
index 4d9458ca8c..dc5e07bff9 100644
--- a/app/api/relationships/relationships.js
+++ b/app/api/relationships/relationships.js
@@ -270,6 +270,20 @@ export default {
       ).map(r => r.sharedId)
     );
 
+    const relTypesToSave = new Set(
+      relsFlat
+        .map(r => (r.template && Object.hasOwn(r.template, '_id') ? r.template._id : r.template))
+        .filter(r => r)
+    );
+
+    const existingRelationshipTypes = await relationtypes.count({
+      _id: { $in: Array.from(relTypesToSave) },
+    });
+
+    if (relTypesToSave.size !== existingRelationshipTypes) {
+      throw new Error('Some relationship types do not exist');
+    }
+
     const relationships = rels.map(_group => {
       let group = _group.filter(r => existingEntities.has(r.entity));
       if (group.length === 1 && !group[0].hub) {
diff --git a/app/api/relationships/specs/relationships.spec.js b/app/api/relationships/specs/relationships.spec.js
index 86cfe45bc8..086cc6c034 100644
--- a/app/api/relationships/specs/relationships.spec.js
+++ b/app/api/relationships/specs/relationships.spec.js
@@ -302,6 +302,22 @@ describe('relationships', () => {
       });
     });
 
+    describe('when creating relationships using non existent relationship types', () => {
+      it('should throw an error', async () => {
+        const nonExistentRelationshipType = db.id();
+        await expect(async () =>
+          relationships.save(
+            [
+              { entity: 'entity3', template: relation2 },
+              { entity: 'entity2', template: nonExistentRelationshipType },
+              { entity: 'entity4', template: null },
+            ],
+            'en'
+          )
+        ).rejects.toBeInstanceOf(Error);
+      });
+    });
+
     describe('when creating relationships to non existent entities', () => {
       it('should not create them', async () => {
         const relations = await relationships.save(
@@ -373,11 +389,17 @@ describe('relationships', () => {
       });
 
       it('should update correctly if template is null', async () => {
-        const reference = await relationships.getById(connectionID1);
+        let reference = await relationships.getById(connectionID1);
         reference.template = { _id: null };
         const [savedReference] = await relationships.save(reference, 'en');
         expect(savedReference.entity).toBe('entity_id');
         expect(savedReference.template).toBe(null);
+
+        reference = await relationships.getById(connectionID1);
+        reference.template = null;
+        const [savedRef2] = await relationships.save(reference, 'en');
+        expect(savedRef2.entity).toBe('entity_id');
+        expect(savedRef2.template).toBe(null);
       });
     });
 
diff --git a/app/api/relationtypes/relationtypes.js b/app/api/relationtypes/relationtypes.js
index bb2ec02088..01b992bdab 100644
--- a/app/api/relationtypes/relationtypes.js
+++ b/app/api/relationtypes/relationtypes.js
@@ -92,6 +92,10 @@ export default {
     return model.get(query);
   },
 
+  count(query) {
+    return model.count(query);
+  },
+
   getById(id) {
     return model.getById(id);
   },
diff --git a/app/api/search.v2/specs/sorting.spec.ts b/app/api/search.v2/specs/sorting.spec.ts
index acca5b8ac6..e89866c68c 100644
--- a/app/api/search.v2/specs/sorting.spec.ts
+++ b/app/api/search.v2/specs/sorting.spec.ts
@@ -41,6 +41,7 @@ describe('Sorting', () => {
 
     await setupTestingEnviroment(
       {
+        relationtypes: [factory.relationType('rel1')],
         templates: [
           factory.template('templateA', [
             factory.property('textProperty', 'text'),