diff --git a/api/src/helper/lib/base-nlp-helper.ts b/api/src/helper/lib/base-nlp-helper.ts
index 7c52e11b..02c30863 100644
--- a/api/src/helper/lib/base-nlp-helper.ts
+++ b/api/src/helper/lib/base-nlp-helper.ts
@@ -151,7 +151,7 @@ export default abstract class BaseNlpHelper<
           })
           .concat({
             entity: 'language',
-            value: s.language.code,
+            value: s.language!.code,
           });
 
         return {
diff --git a/api/src/i18n/services/language.service.ts b/api/src/i18n/services/language.service.ts
index de312cf6..0a7425d5 100644
--- a/api/src/i18n/services/language.service.ts
+++ b/api/src/i18n/services/language.service.ts
@@ -11,9 +11,11 @@ import {
   Inject,
   Injectable,
   InternalServerErrorException,
+  NotFoundException,
 } from '@nestjs/common';
 import { Cache } from 'cache-manager';
 
+import { LoggerService } from '@/logger/logger.service';
 import {
   DEFAULT_LANGUAGE_CACHE_KEY,
   LANGUAGES_CACHE_KEY,
@@ -35,6 +37,7 @@ export class LanguageService extends BaseService<
   constructor(
     readonly repository: LanguageRepository,
     @Inject(CACHE_MANAGER) private readonly cacheManager: Cache,
+    private readonly logger: LoggerService,
   ) {
     super(repository);
   }
@@ -78,6 +81,15 @@ export class LanguageService extends BaseService<
    * @returns A promise that resolves to the `Language` object.
    */
   async getLanguageByCode(code: string) {
-    return await this.findOne({ code });
+    const language = await this.findOne({ code });
+
+    if (!language) {
+      this.logger.warn(`Unable to Language by languageCode ${code}`);
+      throw new NotFoundException(
+        `Language with languageCode ${code} not found`,
+      );
+    }
+
+    return language;
   }
 }
diff --git a/api/src/nlp/controllers/nlp-entity.controller.spec.ts b/api/src/nlp/controllers/nlp-entity.controller.spec.ts
index 22d9dfd8..c33f8955 100644
--- a/api/src/nlp/controllers/nlp-entity.controller.spec.ts
+++ b/api/src/nlp/controllers/nlp-entity.controller.spec.ts
@@ -27,15 +27,16 @@ import {
   closeInMongodConnection,
   rootMongooseTestModule,
 } from '@/utils/test/test';
+import { TFixtures } from '@/utils/test/types';
 
 import { NlpEntityCreateDto } from '../dto/nlp-entity.dto';
 import { NlpEntityRepository } from '../repositories/nlp-entity.repository';
 import { NlpSampleEntityRepository } from '../repositories/nlp-sample-entity.repository';
 import { NlpValueRepository } from '../repositories/nlp-value.repository';
 import {
-  NlpEntityModel,
   NlpEntity,
   NlpEntityFull,
+  NlpEntityModel,
 } from '../schemas/nlp-entity.schema';
 import { NlpSampleEntityModel } from '../schemas/nlp-sample-entity.schema';
 import { NlpValueModel } from '../schemas/nlp-value.schema';
@@ -48,8 +49,8 @@ describe('NlpEntityController', () => {
   let nlpEntityController: NlpEntityController;
   let nlpValueService: NlpValueService;
   let nlpEntityService: NlpEntityService;
-  let intentEntityId: string;
-  let buitInEntityId: string;
+  let intentEntityId: string | null;
+  let buitInEntityId: string | null;
 
   beforeAll(async () => {
     const module: TestingModule = await Test.createTestingModule({
@@ -76,16 +77,18 @@ describe('NlpEntityController', () => {
     nlpValueService = module.get<NlpValueService>(NlpValueService);
     nlpEntityService = module.get<NlpEntityService>(NlpEntityService);
 
-    intentEntityId = (
-      await nlpEntityService.findOne({
-        name: 'intent',
-      })
-    ).id;
-    buitInEntityId = (
-      await nlpEntityService.findOne({
-        name: 'built_in',
-      })
-    ).id;
+    intentEntityId =
+      (
+        await nlpEntityService.findOne({
+          name: 'intent',
+        })
+      )?.id || null;
+    buitInEntityId =
+      (
+        await nlpEntityService.findOne({
+          name: 'built_in',
+        })
+      )?.id || null;
   });
   afterAll(async () => {
     await closeInMongodConnection();
@@ -107,11 +110,13 @@ describe('NlpEntityController', () => {
             ...curr,
             values: nlpValueFixtures.filter(
               ({ entity }) => parseInt(entity) === index,
-            ),
+            ) as NlpEntityFull['values'],
+            lookups: curr.lookups!,
+            builtin: curr.builtin!,
           });
           return acc;
         },
-        [],
+        [] as TFixtures<NlpEntityFull>[],
       );
       expect(result).toEqualPayload(
         entitiesWithValues.sort((a, b) => {
@@ -170,19 +175,19 @@ describe('NlpEntityController', () => {
 
   describe('deleteOne', () => {
     it('should delete a nlp entity', async () => {
-      const result = await nlpEntityController.deleteOne(intentEntityId);
+      const result = await nlpEntityController.deleteOne(intentEntityId!);
       expect(result.deletedCount).toEqual(1);
     });
 
     it('should throw exception when nlp entity id not found', async () => {
       await expect(
-        nlpEntityController.deleteOne(intentEntityId),
+        nlpEntityController.deleteOne(intentEntityId!),
       ).rejects.toThrow(NotFoundException);
     });
 
     it('should throw exception when nlp entity is builtin', async () => {
       await expect(
-        nlpEntityController.deleteOne(buitInEntityId),
+        nlpEntityController.deleteOne(buitInEntityId!),
       ).rejects.toThrow(MethodNotAllowedException);
     });
   });
@@ -192,10 +197,10 @@ describe('NlpEntityController', () => {
       const firstNameEntity = await nlpEntityService.findOne({
         name: 'first_name',
       });
-      const result = await nlpEntityController.findOne(firstNameEntity.id, []);
+      const result = await nlpEntityController.findOne(firstNameEntity!.id, []);
 
       expect(result).toEqualPayload(
-        nlpEntityFixtures.find(({ name }) => name === 'first_name'),
+        nlpEntityFixtures.find(({ name }) => name === 'first_name')!,
       );
     });
 
@@ -206,9 +211,15 @@ describe('NlpEntityController', () => {
       const firstNameValues = await nlpValueService.findOne({ value: 'jhon' });
       const firstNameWithValues: NlpEntityFull = {
         ...firstNameEntity,
-        values: [firstNameValues],
+        values: firstNameValues ? [firstNameValues] : [],
+        name: firstNameEntity!.name,
+        id: firstNameEntity!.id,
+        createdAt: firstNameEntity!.createdAt,
+        updatedAt: firstNameEntity!.updatedAt,
+        lookups: firstNameEntity!.lookups,
+        builtin: firstNameEntity!.builtin,
       };
-      const result = await nlpEntityController.findOne(firstNameEntity.id, [
+      const result = await nlpEntityController.findOne(firstNameEntity!.id, [
         'values',
       ]);
       expect(result).toEqualPayload(firstNameWithValues);
@@ -216,7 +227,7 @@ describe('NlpEntityController', () => {
 
     it('should throw NotFoundException when Id does not exist', async () => {
       await expect(
-        nlpEntityController.findOne(intentEntityId, ['values']),
+        nlpEntityController.findOne(intentEntityId!, ['values']),
       ).rejects.toThrow(NotFoundException);
     });
   });
@@ -233,7 +244,7 @@ describe('NlpEntityController', () => {
         builtin: false,
       };
       const result = await nlpEntityController.updateOne(
-        firstNameEntity.id,
+        firstNameEntity!.id,
         updatedNlpEntity,
       );
       expect(result).toEqualPayload(updatedNlpEntity);
@@ -247,7 +258,7 @@ describe('NlpEntityController', () => {
         builtin: false,
       };
       await expect(
-        nlpEntityController.updateOne(intentEntityId, updateNlpEntity),
+        nlpEntityController.updateOne(intentEntityId!, updateNlpEntity),
       ).rejects.toThrow(NotFoundException);
     });
 
@@ -259,7 +270,7 @@ describe('NlpEntityController', () => {
         builtin: false,
       };
       await expect(
-        nlpEntityController.updateOne(buitInEntityId, updateNlpEntity),
+        nlpEntityController.updateOne(buitInEntityId!, updateNlpEntity),
       ).rejects.toThrow(MethodNotAllowedException);
     });
   });
@@ -276,7 +287,7 @@ describe('NlpEntityController', () => {
             name: 'updated',
           })
         )?.id,
-      ];
+      ] as string[];
 
       const result = await nlpEntityController.deleteMany(entitiesToDelete);
 
diff --git a/api/src/nlp/controllers/nlp-sample.controller.spec.ts b/api/src/nlp/controllers/nlp-sample.controller.spec.ts
index b8d51f9f..e3285931 100644
--- a/api/src/nlp/controllers/nlp-sample.controller.spec.ts
+++ b/api/src/nlp/controllers/nlp-sample.controller.spec.ts
@@ -30,6 +30,7 @@ import {
   closeInMongodConnection,
   rootMongooseTestModule,
 } from '@/utils/test/test';
+import { TFixtures } from '@/utils/test/types';
 
 import { NlpSampleDto } from '../dto/nlp-sample.dto';
 import { NlpEntityRepository } from '../repositories/nlp-entity.repository';
@@ -38,7 +39,11 @@ import { NlpSampleRepository } from '../repositories/nlp-sample.repository';
 import { NlpValueRepository } from '../repositories/nlp-value.repository';
 import { NlpEntityModel } from '../schemas/nlp-entity.schema';
 import { NlpSampleEntityModel } from '../schemas/nlp-sample-entity.schema';
-import { NlpSample, NlpSampleModel } from '../schemas/nlp-sample.schema';
+import {
+  NlpSample,
+  NlpSampleFull,
+  NlpSampleModel,
+} from '../schemas/nlp-sample.schema';
 import { NlpValueModel } from '../schemas/nlp-value.schema';
 import { NlpSampleState } from '../schemas/types';
 import { NlpEntityService } from '../services/nlp-entity.service';
@@ -55,7 +60,7 @@ describe('NlpSampleController', () => {
   let nlpEntityService: NlpEntityService;
   let nlpValueService: NlpValueService;
   let languageService: LanguageService;
-  let byeJhonSampleId: string;
+  let byeJhonSampleId: string | null;
   let languages: Language[];
 
   beforeAll(async () => {
@@ -115,11 +120,12 @@ describe('NlpSampleController', () => {
     nlpSampleService = module.get<NlpSampleService>(NlpSampleService);
     nlpEntityService = module.get<NlpEntityService>(NlpEntityService);
     nlpValueService = module.get<NlpValueService>(NlpValueService);
-    byeJhonSampleId = (
-      await nlpSampleService.findOne({
-        text: 'Bye Jhon',
-      })
-    ).id;
+    byeJhonSampleId =
+      (
+        await nlpSampleService.findOne({
+          text: 'Bye Jhon',
+        })
+      )?.id || null;
     languageService = module.get<LanguageService>(LanguageService);
     languages = await languageService.findAll();
   });
@@ -143,15 +149,16 @@ describe('NlpSampleController', () => {
         (acc, currSample) => {
           const sampleWithEntities = {
             ...currSample,
-            entities: nlpSampleEntities.filter((currSampleEntity) => {
-              return currSampleEntity.sample === currSample.id;
-            }),
-            language: languages.find((lang) => lang.id === currSample.language),
+            entities: nlpSampleEntities.filter(
+              (currSampleEntity) => currSampleEntity.sample === currSample.id,
+            ),
+            language:
+              languages.find((lang) => lang.id === currSample.language) || null,
           };
           acc.push(sampleWithEntities);
           return acc;
         },
-        [],
+        [] as TFixtures<NlpSampleFull>[],
       );
 
       expect(result).toEqualPayload(nlpSampleFixturesWithEntities);
@@ -167,7 +174,7 @@ describe('NlpSampleController', () => {
       expect(result).toEqualPayload(
         nlpSampleFixtures.map((sample) => ({
           ...sample,
-          language: languages[sample.language].id,
+          language: sample.language ? languages[sample.language].id : null,
         })),
       );
     });
@@ -201,13 +208,13 @@ describe('NlpSampleController', () => {
 
   describe('deleteOne', () => {
     it('should delete a nlp sample', async () => {
-      const result = await nlpSampleController.deleteOne(byeJhonSampleId);
+      const result = await nlpSampleController.deleteOne(byeJhonSampleId!);
       expect(result.deletedCount).toEqual(1);
     });
 
     it('should throw exception when nlp sample id not found', async () => {
       await expect(
-        nlpSampleController.deleteOne(byeJhonSampleId),
+        nlpSampleController.deleteOne(byeJhonSampleId!),
       ).rejects.toThrow(NotFoundException);
     });
   });
@@ -217,12 +224,14 @@ describe('NlpSampleController', () => {
       const yessSample = await nlpSampleService.findOne({
         text: 'yess',
       });
-      const result = await nlpSampleController.findOne(yessSample.id, [
+      const result = await nlpSampleController.findOne(yessSample!.id, [
         'invalidCreteria',
       ]);
       expect(result).toEqualPayload({
         ...nlpSampleFixtures[0],
-        language: languages[nlpSampleFixtures[0].language].id,
+        language: nlpSampleFixtures[0].language
+          ? languages[nlpSampleFixtures?.[0]?.language]?.id
+          : null,
       });
     });
 
@@ -231,22 +240,24 @@ describe('NlpSampleController', () => {
         text: 'yess',
       });
       const yessSampleEntity = await nlpSampleEntityService.findOne({
-        sample: yessSample.id,
+        sample: yessSample!.id,
       });
-      const result = await nlpSampleController.findOne(yessSample.id, [
+      const result = await nlpSampleController.findOne(yessSample!.id, [
         'entities',
       ]);
       const samplesWithEntities = {
         ...nlpSampleFixtures[0],
         entities: [yessSampleEntity],
-        language: languages[nlpSampleFixtures[0].language],
+        language: nlpSampleFixtures[0].language
+          ? languages[nlpSampleFixtures[0].language]
+          : null,
       };
       expect(result).toEqualPayload(samplesWithEntities);
     });
 
     it('should throw NotFoundException when Id does not exist', async () => {
       await expect(
-        nlpSampleController.findOne(byeJhonSampleId, ['entities']),
+        nlpSampleController.findOne(byeJhonSampleId!, ['entities']),
       ).rejects.toThrow(NotFoundException);
     });
   });
@@ -259,7 +270,7 @@ describe('NlpSampleController', () => {
       const frLang = await languageService.findOne({
         code: 'fr',
       });
-      const result = await nlpSampleController.updateOne(yessSample.id, {
+      const result = await nlpSampleController.updateOne(yessSample!.id, {
         text: 'updated',
         trained: true,
         type: NlpSampleState.test,
@@ -288,12 +299,12 @@ describe('NlpSampleController', () => {
       expect(result.type).toEqual(updatedSample.type);
       expect(result.trained).toEqual(updatedSample.trained);
       expect(result.entities).toMatchObject(updatedSample.entities);
-      expect(result.language).toEqualPayload(updatedSample.language);
+      expect(result.language).toEqualPayload(updatedSample.language!);
     });
 
     it('should throw exception when nlp sample id not found', async () => {
       await expect(
-        nlpSampleController.updateOne(byeJhonSampleId, {
+        nlpSampleController.updateOne(byeJhonSampleId!, {
           text: 'updated',
           trained: true,
           type: NlpSampleState.test,
@@ -366,13 +377,13 @@ describe('NlpSampleController', () => {
         value: 'price',
         expressions: [],
         builtin: false,
-        entity: priceValueEntity.id,
+        entity: priceValueEntity!.id,
       };
       const textSample = {
         text: 'How much does a BMW cost?',
         trained: false,
         type: 'train',
-        language: language.id,
+        language: language!.id,
       };
 
       expect(intentEntityResult).toEqualPayload(intentEntity);
@@ -389,13 +400,13 @@ describe('NlpSampleController', () => {
           await nlpSampleService.findOne({
             text: 'How much does a BMW cost?',
           })
-        ).id,
+        )?.id,
         (
           await nlpSampleService.findOne({
             text: 'text1',
           })
-        ).id,
-      ];
+        )?.id,
+      ] as string[];
 
       const result = await nlpSampleController.deleteMany(samplesToDelete);
 
diff --git a/api/src/nlp/controllers/nlp-sample.controller.ts b/api/src/nlp/controllers/nlp-sample.controller.ts
index fbeed58b..cc49d41a 100644
--- a/api/src/nlp/controllers/nlp-sample.controller.ts
+++ b/api/src/nlp/controllers/nlp-sample.controller.ts
@@ -42,7 +42,7 @@ import { PopulatePipe } from '@/utils/pipes/populate.pipe';
 import { SearchFilterPipe } from '@/utils/pipes/search-filter.pipe';
 import { TFilterQuery } from '@/utils/types/filter.types';
 
-import { NlpSampleDto } from '../dto/nlp-sample.dto';
+import { NlpSampleDto, TNlpSampleDto } from '../dto/nlp-sample.dto';
 import {
   NlpSample,
   NlpSampleFull,
@@ -60,7 +60,8 @@ export class NlpSampleController extends BaseController<
   NlpSample,
   NlpSampleStub,
   NlpSamplePopulate,
-  NlpSampleFull
+  NlpSampleFull,
+  TNlpSampleDto
 > {
   constructor(
     private readonly nlpSampleService: NlpSampleService,
@@ -128,15 +129,18 @@ export class NlpSampleController extends BaseController<
     }: NlpSampleDto,
   ): Promise<NlpSampleFull> {
     const language = await this.languageService.getLanguageByCode(languageCode);
+
     const nlpSample = await this.nlpSampleService.create({
       ...createNlpSampleDto,
       language: language.id,
     });
 
-    const entities = await this.nlpSampleEntityService.storeSampleEntities(
-      nlpSample,
-      nlpEntities,
-    );
+    const entities = nlpEntities
+      ? await this.nlpSampleEntityService.storeSampleEntities(
+          nlpSample,
+          nlpEntities,
+        )
+      : [];
 
     return {
       ...nlpSample,
@@ -202,7 +206,7 @@ export class NlpSampleController extends BaseController<
 
     try {
       const helper = await this.helperService.getDefaultNluHelper();
-      const response = await helper.train(samples, entities);
+      const response = await helper.train?.(samples, entities);
       // Mark samples as trained
       await this.nlpSampleService.updateMany(
         { type: 'train' },
@@ -228,7 +232,7 @@ export class NlpSampleController extends BaseController<
       await this.getSamplesAndEntitiesByType('test');
 
     const helper = await this.helperService.getDefaultNluHelper();
-    return await helper.evaluate(samples, entities);
+    return await helper.evaluate?.(samples, entities);
   }
 
   /**
@@ -294,6 +298,7 @@ export class NlpSampleController extends BaseController<
     @Body() { entities, language: languageCode, ...sampleAttrs }: NlpSampleDto,
   ): Promise<NlpSampleFull> {
     const language = await this.languageService.getLanguageByCode(languageCode);
+
     const sample = await this.nlpSampleService.updateOne(id, {
       ...sampleAttrs,
       language: language.id,
@@ -308,7 +313,10 @@ export class NlpSampleController extends BaseController<
     await this.nlpSampleEntityService.deleteMany({ sample: id });
 
     const updatedSampleEntities =
-      await this.nlpSampleEntityService.storeSampleEntities(sample, entities);
+      await this.nlpSampleEntityService.storeSampleEntities(
+        sample,
+        entities || [],
+      );
 
     return {
       ...sample,
diff --git a/api/src/nlp/controllers/nlp-value.controller.spec.ts b/api/src/nlp/controllers/nlp-value.controller.spec.ts
index bb4a56f4..58be7aa8 100644
--- a/api/src/nlp/controllers/nlp-value.controller.spec.ts
+++ b/api/src/nlp/controllers/nlp-value.controller.spec.ts
@@ -22,6 +22,7 @@ import {
   closeInMongodConnection,
   rootMongooseTestModule,
 } from '@/utils/test/test';
+import { TFixtures } from '@/utils/test/types';
 
 import { NlpValueCreateDto } from '../dto/nlp-value.dto';
 import { NlpEntityRepository } from '../repositories/nlp-entity.repository';
@@ -29,7 +30,11 @@ import { NlpSampleEntityRepository } from '../repositories/nlp-sample-entity.rep
 import { NlpValueRepository } from '../repositories/nlp-value.repository';
 import { NlpEntityModel } from '../schemas/nlp-entity.schema';
 import { NlpSampleEntityModel } from '../schemas/nlp-sample-entity.schema';
-import { NlpValueModel, NlpValue } from '../schemas/nlp-value.schema';
+import {
+  NlpValue,
+  NlpValueFull,
+  NlpValueModel,
+} from '../schemas/nlp-value.schema';
 import { NlpEntityService } from '../services/nlp-entity.service';
 import { NlpValueService } from '../services/nlp-value.service';
 
@@ -39,9 +44,9 @@ describe('NlpValueController', () => {
   let nlpValueController: NlpValueController;
   let nlpValueService: NlpValueService;
   let nlpEntityService: NlpEntityService;
-  let jhonNlpValue: NlpValue;
-  let positiveValue: NlpValue;
-  let negativeValue: NlpValue;
+  let jhonNlpValue: NlpValue | null;
+  let positiveValue: NlpValue | null;
+  let negativeValue: NlpValue | null;
 
   beforeAll(async () => {
     const module: TestingModule = await Test.createTestingModule({
@@ -92,11 +97,16 @@ describe('NlpValueController', () => {
         (acc, curr) => {
           acc.push({
             ...curr,
-            entity: nlpEntityFixtures[parseInt(curr.entity)],
+            entity: nlpEntityFixtures[
+              parseInt(curr.entity)
+            ] as NlpValueFull['entity'],
+            builtin: curr.builtin!,
+            expressions: curr.expressions!,
+            metadata: curr.metadata!,
           });
           return acc;
         },
-        [],
+        [] as TFixtures<NlpValueFull>[],
       );
       expect(result).toEqualPayload(nlpValueFixturesWithEntities);
     });
@@ -116,11 +126,14 @@ describe('NlpValueController', () => {
           const ValueWithEntities = {
             ...curr,
             entity: nlpEntities[parseInt(curr.entity)].id,
+            expressions: curr.expressions!,
+            metadata: curr.metadata!,
+            builtin: curr.builtin!,
           };
           acc.push(ValueWithEntities);
           return acc;
         },
-        [],
+        [] as TFixtures<NlpValue>[],
       );
       expect(result).toEqualPayload(nlpValueFixturesWithEntities);
     });
@@ -151,20 +164,20 @@ describe('NlpValueController', () => {
 
   describe('deleteOne', () => {
     it('should delete a nlp Value', async () => {
-      const result = await nlpValueController.deleteOne(jhonNlpValue.id);
+      const result = await nlpValueController.deleteOne(jhonNlpValue!.id);
       expect(result.deletedCount).toEqual(1);
     });
 
     it('should throw exception when nlp Value id not found', async () => {
       await expect(
-        nlpValueController.deleteOne(jhonNlpValue.id),
+        nlpValueController.deleteOne(jhonNlpValue!.id),
       ).rejects.toThrow(NotFoundException);
     });
   });
 
   describe('findOne', () => {
     it('should get a nlp Value', async () => {
-      const result = await nlpValueController.findOne(positiveValue.id, [
+      const result = await nlpValueController.findOne(positiveValue!.id, [
         'invalidCreteria',
       ]);
       const intentNlpEntity = await nlpEntityService.findOne({
@@ -172,7 +185,7 @@ describe('NlpValueController', () => {
       });
       const valueWithEntity = {
         ...nlpValueFixtures[0],
-        entity: intentNlpEntity.id,
+        entity: intentNlpEntity!.id,
       };
 
       expect(result).toEqualPayload(valueWithEntity);
@@ -182,7 +195,7 @@ describe('NlpValueController', () => {
       const intentNlpEntity = await nlpEntityService.findOne({
         name: 'intent',
       });
-      const result = await nlpValueController.findOne(positiveValue.id, [
+      const result = await nlpValueController.findOne(positiveValue!.id, [
         'entity',
       ]);
       const valueWithEntity = {
@@ -194,7 +207,7 @@ describe('NlpValueController', () => {
 
     it('should throw NotFoundException when Id does not exist', async () => {
       await expect(
-        nlpValueController.findOne(jhonNlpValue.id, ['entity']),
+        nlpValueController.findOne(jhonNlpValue!.id, ['entity']),
       ).rejects.toThrow(NotFoundException);
     });
   });
@@ -205,13 +218,13 @@ describe('NlpValueController', () => {
         name: 'intent',
       });
       const updatedValue = {
-        entity: intentNlpEntity.id,
+        entity: intentNlpEntity!.id,
         value: 'updated',
         expressions: [],
         builtin: true,
       };
       const result = await nlpValueController.updateOne(
-        positiveValue.id,
+        positiveValue!.id,
         updatedValue,
       );
       expect(result).toEqualPayload(updatedValue);
@@ -222,8 +235,8 @@ describe('NlpValueController', () => {
         name: 'intent',
       });
       await expect(
-        nlpValueController.updateOne(jhonNlpValue.id, {
-          entity: intentNlpEntity.id,
+        nlpValueController.updateOne(jhonNlpValue!.id, {
+          entity: intentNlpEntity!.id,
           value: 'updated',
           expressions: [],
           builtin: true,
@@ -233,7 +246,7 @@ describe('NlpValueController', () => {
   });
   describe('deleteMany', () => {
     it('should delete multiple nlp values', async () => {
-      const valuesToDelete = [positiveValue.id, negativeValue.id];
+      const valuesToDelete = [positiveValue!.id, negativeValue!.id];
 
       const result = await nlpValueController.deleteMany(valuesToDelete);
 
diff --git a/api/src/nlp/repositories/nlp-entity.repository.spec.ts b/api/src/nlp/repositories/nlp-entity.repository.spec.ts
index 4ed70ca9..a4bd2a17 100644
--- a/api/src/nlp/repositories/nlp-entity.repository.spec.ts
+++ b/api/src/nlp/repositories/nlp-entity.repository.spec.ts
@@ -18,7 +18,7 @@ import {
   rootMongooseTestModule,
 } from '@/utils/test/test';
 
-import { NlpEntityModel, NlpEntity } from '../schemas/nlp-entity.schema';
+import { NlpEntity, NlpEntityModel } from '../schemas/nlp-entity.schema';
 import { NlpSampleEntityModel } from '../schemas/nlp-sample-entity.schema';
 import { NlpValueModel } from '../schemas/nlp-value.schema';
 
@@ -29,7 +29,7 @@ import { NlpValueRepository } from './nlp-value.repository';
 describe('NlpEntityRepository', () => {
   let nlpEntityRepository: NlpEntityRepository;
   let nlpValueRepository: NlpValueRepository;
-  let firstNameNlpEntity: NlpEntity;
+  let firstNameNlpEntity: NlpEntity | null;
 
   beforeAll(async () => {
     const module: TestingModule = await Test.createTestingModule({
@@ -66,12 +66,12 @@ describe('NlpEntityRepository', () => {
       const intentNlpEntity = await nlpEntityRepository.findOne({
         name: 'intent',
       });
-      const result = await nlpEntityRepository.deleteOne(intentNlpEntity.id);
+      const result = await nlpEntityRepository.deleteOne(intentNlpEntity!.id);
 
       expect(result.deletedCount).toEqual(1);
 
       const intentNlpValues = await nlpValueRepository.find({
-        entity: intentNlpEntity.id,
+        entity: intentNlpEntity!.id,
       });
 
       expect(intentNlpValues.length).toEqual(0);
@@ -81,10 +81,10 @@ describe('NlpEntityRepository', () => {
   describe('findOneAndPopulate', () => {
     it('should return a nlp entity with populate', async () => {
       const firstNameValues = await nlpValueRepository.find({
-        entity: firstNameNlpEntity.id,
+        entity: firstNameNlpEntity!.id,
       });
       const result = await nlpEntityRepository.findOneAndPopulate(
-        firstNameNlpEntity.id,
+        firstNameNlpEntity!.id,
       );
       expect(result).toEqualPayload({
         ...nlpEntityFixtures[1],
@@ -99,15 +99,15 @@ describe('NlpEntityRepository', () => {
         sort: ['name', 'desc'],
       });
       const firstNameValues = await nlpValueRepository.find({
-        entity: firstNameNlpEntity.id,
+        entity: firstNameNlpEntity!.id,
       });
       const result = await nlpEntityRepository.findPageAndPopulate(
-        { _id: firstNameNlpEntity.id },
+        { _id: firstNameNlpEntity!.id },
         pageQuery,
       );
       expect(result).toEqualPayload([
         {
-          id: firstNameNlpEntity.id,
+          id: firstNameNlpEntity!.id,
           ...nlpEntityFixtures[1],
           values: firstNameValues,
         },
diff --git a/api/src/nlp/repositories/nlp-sample-entity.repository.spec.ts b/api/src/nlp/repositories/nlp-sample-entity.repository.spec.ts
index 801f5e5b..50494a7b 100644
--- a/api/src/nlp/repositories/nlp-sample-entity.repository.spec.ts
+++ b/api/src/nlp/repositories/nlp-sample-entity.repository.spec.ts
@@ -23,14 +23,16 @@ import {
   closeInMongodConnection,
   rootMongooseTestModule,
 } from '@/utils/test/test';
+import { TFixtures } from '@/utils/test/types';
 
-import { NlpEntityModel, NlpEntity } from '../schemas/nlp-entity.schema';
+import { NlpEntity, NlpEntityModel } from '../schemas/nlp-entity.schema';
 import {
-  NlpSampleEntityModel,
   NlpSampleEntity,
+  NlpSampleEntityFull,
+  NlpSampleEntityModel,
 } from '../schemas/nlp-sample-entity.schema';
 import { NlpSampleModel } from '../schemas/nlp-sample.schema';
-import { NlpValueModel } from '../schemas/nlp-value.schema';
+import { NlpValueModel, NlpValueStub } from '../schemas/nlp-value.schema';
 
 import { NlpEntityRepository } from './nlp-entity.repository';
 import { NlpSampleEntityRepository } from './nlp-sample-entity.repository';
@@ -91,7 +93,7 @@ describe('NlpSampleEntityRepository', () => {
         value: { ...nlpValueFixtures[0], entity: nlpEntities[0].id },
         sample: {
           ...nlpSampleFixtures[0],
-          language: languages[nlpSampleFixtures[0].language].id,
+          language: languages[nlpSampleFixtures[0].language!].id,
         },
       });
     });
@@ -111,11 +113,14 @@ describe('NlpSampleEntityRepository', () => {
           const ValueWithEntities = {
             ...curr,
             entity: nlpEntities[0].id,
+            expressions: curr.expressions!,
+            builtin: curr.builtin!,
+            metadata: curr.metadata!,
           };
           acc.push(ValueWithEntities);
           return acc;
         },
-        [],
+        [] as TFixtures<NlpValueStub>[],
       );
       nlpValueFixturesWithEntities[2] = {
         ...nlpValueFixturesWithEntities[2],
@@ -135,7 +140,7 @@ describe('NlpSampleEntityRepository', () => {
           };
           acc.push(sampleEntityWithPopulate);
           return acc;
-        }, []);
+        }, [] as TFixtures<NlpSampleEntityFull>[]);
       expect(result).toEqualPayload(nlpSampleEntityFixturesWithPopulate);
     });
   });
diff --git a/api/src/nlp/repositories/nlp-sample.repository.spec.ts b/api/src/nlp/repositories/nlp-sample.repository.spec.ts
index b5dd9e0b..4c2d00c8 100644
--- a/api/src/nlp/repositories/nlp-sample.repository.spec.ts
+++ b/api/src/nlp/repositories/nlp-sample.repository.spec.ts
@@ -19,12 +19,17 @@ import {
   closeInMongodConnection,
   rootMongooseTestModule,
 } from '@/utils/test/test';
+import { TFixtures } from '@/utils/test/types';
 
 import {
-  NlpSampleEntityModel,
   NlpSampleEntity,
+  NlpSampleEntityModel,
 } from '../schemas/nlp-sample-entity.schema';
-import { NlpSampleModel, NlpSample } from '../schemas/nlp-sample.schema';
+import {
+  NlpSample,
+  NlpSampleFull,
+  NlpSampleModel,
+} from '../schemas/nlp-sample.schema';
 
 import { NlpSampleEntityRepository } from './nlp-sample-entity.repository';
 import { NlpSampleRepository } from './nlp-sample.repository';
@@ -33,8 +38,8 @@ describe('NlpSampleRepository', () => {
   let nlpSampleRepository: NlpSampleRepository;
   let nlpSampleEntityRepository: NlpSampleEntityRepository;
   let languageRepository: LanguageRepository;
-  let nlpSampleEntity: NlpSampleEntity;
-  let noNlpSample: NlpSample;
+  let nlpSampleEntity: NlpSampleEntity | null;
+  let noNlpSample: NlpSample | null;
   let languages: Language[];
 
   beforeAll(async () => {
@@ -61,7 +66,7 @@ describe('NlpSampleRepository', () => {
     languageRepository = module.get<LanguageRepository>(LanguageRepository);
     noNlpSample = await nlpSampleRepository.findOne({ text: 'No' });
     nlpSampleEntity = await nlpSampleEntityRepository.findOne({
-      sample: noNlpSample.id,
+      sample: noNlpSample!.id,
     });
     languages = await languageRepository.findAll();
   });
@@ -75,12 +80,12 @@ describe('NlpSampleRepository', () => {
   describe('findOneAndPopulate', () => {
     it('should return a nlp Sample with populate', async () => {
       const result = await nlpSampleRepository.findOneAndPopulate(
-        noNlpSample.id,
+        noNlpSample!.id,
       );
       expect(result).toEqualPayload({
         ...nlpSampleFixtures[1],
         entities: [nlpSampleEntity],
-        language: languages[nlpSampleFixtures[1].language],
+        language: languages[nlpSampleFixtures[1].language!],
       });
     });
   });
@@ -104,12 +109,13 @@ describe('NlpSampleRepository', () => {
             entities: nlpSampleEntities.filter((currSampleEntity) => {
               return currSampleEntity.sample === currSample.id;
             }),
-            language: languages.find((lang) => currSample.language === lang.id),
+            language:
+              languages.find((lang) => currSample.language === lang.id) || null,
           };
           acc.push(sampleWithEntities);
           return acc;
         },
-        [],
+        [] as TFixtures<NlpSampleFull>[],
       );
       expect(result).toEqualPayload(nlpSampleFixturesWithEntities);
     });
@@ -130,10 +136,10 @@ describe('NlpSampleRepository', () => {
 
   describe('The deleteCascadeOne function', () => {
     it('should delete a nlp Sample', async () => {
-      const result = await nlpSampleRepository.deleteOne(noNlpSample.id);
+      const result = await nlpSampleRepository.deleteOne(noNlpSample!.id);
       expect(result.deletedCount).toEqual(1);
       const sampleEntities = await nlpSampleEntityRepository.find({
-        sample: noNlpSample.id,
+        sample: noNlpSample!.id,
       });
       expect(sampleEntities.length).toEqual(0);
     });
diff --git a/api/src/nlp/repositories/nlp-value.repository.spec.ts b/api/src/nlp/repositories/nlp-value.repository.spec.ts
index ffef47f9..3186cc26 100644
--- a/api/src/nlp/repositories/nlp-value.repository.spec.ts
+++ b/api/src/nlp/repositories/nlp-value.repository.spec.ts
@@ -18,10 +18,15 @@ import {
   closeInMongodConnection,
   rootMongooseTestModule,
 } from '@/utils/test/test';
+import { TFixtures } from '@/utils/test/types';
 
 import { NlpEntityModel } from '../schemas/nlp-entity.schema';
 import { NlpSampleEntityModel } from '../schemas/nlp-sample-entity.schema';
-import { NlpValue, NlpValueModel } from '../schemas/nlp-value.schema';
+import {
+  NlpValue,
+  NlpValueFull,
+  NlpValueModel,
+} from '../schemas/nlp-value.schema';
 
 import { NlpSampleEntityRepository } from './nlp-sample-entity.repository';
 import { NlpValueRepository } from './nlp-value.repository';
@@ -81,12 +86,17 @@ describe('NlpValueRepository', () => {
         (acc, curr) => {
           const ValueWithEntities = {
             ...curr,
-            entity: nlpEntityFixtures[parseInt(curr.entity)],
+            entity: nlpEntityFixtures[
+              parseInt(curr.entity)
+            ] as NlpValueFull['entity'],
+            builtin: curr.builtin!,
+            expressions: curr.expressions!,
+            metadata: curr.metadata!,
           };
           acc.push(ValueWithEntities);
           return acc;
         },
-        [],
+        [] as TFixtures<NlpValueFull>[],
       );
       expect(result).toEqualPayload(nlpValueFixturesWithEntities);
     });
diff --git a/api/src/nlp/services/nlp-entity.service.spec.ts b/api/src/nlp/services/nlp-entity.service.spec.ts
index ffb53216..76b78233 100644
--- a/api/src/nlp/services/nlp-entity.service.spec.ts
+++ b/api/src/nlp/services/nlp-entity.service.spec.ts
@@ -21,7 +21,7 @@ import {
 import { NlpEntityRepository } from '../repositories/nlp-entity.repository';
 import { NlpSampleEntityRepository } from '../repositories/nlp-sample-entity.repository';
 import { NlpValueRepository } from '../repositories/nlp-value.repository';
-import { NlpEntityModel, NlpEntity } from '../schemas/nlp-entity.schema';
+import { NlpEntity, NlpEntityModel } from '../schemas/nlp-entity.schema';
 import { NlpSampleEntityModel } from '../schemas/nlp-sample-entity.schema';
 import { NlpValueModel } from '../schemas/nlp-value.schema';
 
@@ -69,7 +69,7 @@ describe('nlpEntityService', () => {
         name: 'intent',
       });
       const result = await nlpEntityService.deleteCascadeOne(
-        intentNlpEntity.id,
+        intentNlpEntity!.id,
       );
       expect(result.deletedCount).toEqual(1);
     });
@@ -81,13 +81,13 @@ describe('nlpEntityService', () => {
         name: 'first_name',
       });
       const result = await nlpEntityService.findOneAndPopulate(
-        firstNameNlpEntity.id,
+        firstNameNlpEntity!.id,
       );
       const firstNameValues = await nlpValueRepository.findOne({
-        entity: firstNameNlpEntity.id,
+        entity: firstNameNlpEntity!.id,
       });
       const entityWithValues = {
-        id: firstNameNlpEntity.id,
+        id: firstNameNlpEntity!.id,
         ...nlpEntityFixtures[1],
         values: [firstNameValues],
       };
@@ -102,15 +102,15 @@ describe('nlpEntityService', () => {
         name: 'first_name',
       });
       const result = await nlpEntityService.findPageAndPopulate(
-        { _id: firstNameNlpEntity.id },
+        { _id: firstNameNlpEntity!.id },
         pageQuery,
       );
       const firstNameValues = await nlpValueRepository.findOne({
-        entity: firstNameNlpEntity.id,
+        entity: firstNameNlpEntity!.id,
       });
       const entitiesWithValues = [
         {
-          id: firstNameNlpEntity.id,
+          id: firstNameNlpEntity!.id,
           ...nlpEntityFixtures[1],
           values: [firstNameValues],
         },
@@ -139,12 +139,12 @@ describe('nlpEntityService', () => {
       const deValue = await nlpValueRepository.findOne({ value: 'de' });
       const storedEntites = [
         {
-          entity: intentEntity.id,
-          value: nameValue.id,
+          entity: intentEntity!.id,
+          value: nameValue!.id,
         },
         {
-          entity: languageEntity.id,
-          value: deValue.id,
+          entity: languageEntity!.id,
+          value: deValue!.id,
         },
       ];
 
diff --git a/api/src/nlp/services/nlp-sample-entity.service.spec.ts b/api/src/nlp/services/nlp-sample-entity.service.spec.ts
index 72a42011..94707a0a 100644
--- a/api/src/nlp/services/nlp-sample-entity.service.spec.ts
+++ b/api/src/nlp/services/nlp-sample-entity.service.spec.ts
@@ -23,17 +23,23 @@ import {
   closeInMongodConnection,
   rootMongooseTestModule,
 } from '@/utils/test/test';
+import { TFixtures } from '@/utils/test/types';
 
 import { NlpEntityRepository } from '../repositories/nlp-entity.repository';
 import { NlpSampleEntityRepository } from '../repositories/nlp-sample-entity.repository';
 import { NlpValueRepository } from '../repositories/nlp-value.repository';
-import { NlpEntityModel, NlpEntity } from '../schemas/nlp-entity.schema';
+import { NlpEntity, NlpEntityModel } from '../schemas/nlp-entity.schema';
 import {
-  NlpSampleEntityModel,
   NlpSampleEntity,
+  NlpSampleEntityFull,
+  NlpSampleEntityModel,
 } from '../schemas/nlp-sample-entity.schema';
 import { NlpSample, NlpSampleModel } from '../schemas/nlp-sample.schema';
-import { NlpValue, NlpValueModel } from '../schemas/nlp-value.schema';
+import {
+  NlpValue,
+  NlpValueModel,
+  NlpValueStub,
+} from '../schemas/nlp-value.schema';
 
 import { NlpEntityService } from './nlp-entity.service';
 import { NlpSampleEntityService } from './nlp-sample-entity.service';
@@ -91,9 +97,7 @@ describe('NlpSampleEntityService', () => {
     languages = await languageRepository.findAll();
   });
 
-  afterAll(async () => {
-    await closeInMongodConnection();
-  });
+  afterAll(closeInMongodConnection);
 
   afterEach(jest.clearAllMocks);
 
@@ -108,7 +112,7 @@ describe('NlpSampleEntityService', () => {
         value: { ...nlpValueFixtures[0], entity: nlpEntities[0].id },
         sample: {
           ...nlpSampleFixtures[0],
-          language: languages[nlpSampleFixtures[0].language].id,
+          language: languages[nlpSampleFixtures[0].language!].id,
         },
       };
       expect(result).toEqualPayload(sampleEntityWithPopulate);
@@ -129,11 +133,14 @@ describe('NlpSampleEntityService', () => {
           const ValueWithEntities = {
             ...curr,
             entity: nlpEntities[0].id,
+            expressions: curr.expressions!,
+            builtin: curr.builtin!,
+            metadata: curr.metadata!,
           };
           acc.push(ValueWithEntities);
           return acc;
         },
-        [],
+        [] as TFixtures<NlpValueStub>[],
       );
       nlpValueFixturesWithEntities[2] = {
         ...nlpValueFixturesWithEntities[2],
@@ -153,7 +160,7 @@ describe('NlpSampleEntityService', () => {
           };
           acc.push(sampleEntityWithPopulate);
           return acc;
-        }, []);
+        }, [] as TFixtures<NlpSampleEntityFull>[]);
       expect(result).toEqualPayload(nlpSampleEntityFixturesWithPopulate);
     });
   });
diff --git a/api/src/nlp/services/nlp-sample.service.spec.ts b/api/src/nlp/services/nlp-sample.service.spec.ts
index 3b62973b..38deff34 100644
--- a/api/src/nlp/services/nlp-sample.service.spec.ts
+++ b/api/src/nlp/services/nlp-sample.service.spec.ts
@@ -33,7 +33,11 @@ import {
   NlpSampleEntity,
   NlpSampleEntityModel,
 } from '../schemas/nlp-sample-entity.schema';
-import { NlpSample, NlpSampleModel } from '../schemas/nlp-sample.schema';
+import {
+  NlpSample,
+  NlpSampleFull,
+  NlpSampleModel,
+} from '../schemas/nlp-sample.schema';
 import { NlpValueModel } from '../schemas/nlp-value.schema';
 
 import { NlpEntityService } from './nlp-entity.service';
@@ -49,8 +53,8 @@ describe('NlpSampleService', () => {
   let nlpSampleEntityRepository: NlpSampleEntityRepository;
   let nlpSampleRepository: NlpSampleRepository;
   let languageRepository: LanguageRepository;
-  let noNlpSample: NlpSample;
-  let nlpSampleEntity: NlpSampleEntity;
+  let noNlpSample: NlpSample | null;
+  let nlpSampleEntity: NlpSampleEntity | null;
   let languages: Language[];
 
   beforeAll(async () => {
@@ -104,7 +108,7 @@ describe('NlpSampleService', () => {
     languageRepository = module.get<LanguageRepository>(LanguageRepository);
     noNlpSample = await nlpSampleService.findOne({ text: 'No' });
     nlpSampleEntity = await nlpSampleEntityRepository.findOne({
-      sample: noNlpSample.id,
+      sample: noNlpSample!.id,
     });
     languages = await languageRepository.findAll();
   });
@@ -117,11 +121,11 @@ describe('NlpSampleService', () => {
 
   describe('findOneAndPopulate', () => {
     it('should return a nlp Sample with populate', async () => {
-      const result = await nlpSampleService.findOneAndPopulate(noNlpSample.id);
+      const result = await nlpSampleService.findOneAndPopulate(noNlpSample!.id);
       const sampleWithEntities = {
         ...nlpSampleFixtures[1],
         entities: [nlpSampleEntity],
-        language: languages[nlpSampleFixtures[1].language],
+        language: languages[nlpSampleFixtures[1].language!],
       };
       expect(result).toEqualPayload(sampleWithEntities);
     });
@@ -141,12 +145,13 @@ describe('NlpSampleService', () => {
             entities: nlpSampleEntities.filter((currSampleEntity) => {
               return currSampleEntity.sample === currSample.id;
             }),
-            language: languages.find((lang) => lang.id === currSample.language),
+            language:
+              languages.find((lang) => lang.id === currSample.language) || null,
           };
           acc.push(sampleWithEntities);
           return acc;
         },
-        [],
+        [] as NlpSampleFull[],
       );
       expect(result).toEqualPayload(nlpSampleFixturesWithEntities);
     });
@@ -167,7 +172,7 @@ describe('NlpSampleService', () => {
 
   describe('The deleteCascadeOne function', () => {
     it('should delete a nlp Sample', async () => {
-      const result = await nlpSampleService.deleteOne(noNlpSample.id);
+      const result = await nlpSampleService.deleteOne(noNlpSample!.id);
       expect(result.deletedCount).toEqual(1);
     });
   });
diff --git a/api/src/nlp/services/nlp-value.service.spec.ts b/api/src/nlp/services/nlp-value.service.spec.ts
index c5aeb79a..35202015 100644
--- a/api/src/nlp/services/nlp-value.service.spec.ts
+++ b/api/src/nlp/services/nlp-value.service.spec.ts
@@ -10,6 +10,7 @@ import { EventEmitter2 } from '@nestjs/event-emitter';
 import { MongooseModule } from '@nestjs/mongoose';
 import { Test, TestingModule } from '@nestjs/testing';
 
+import { BaseSchema } from '@/utils/generics/base-schema';
 import { nlpEntityFixtures } from '@/utils/test/fixtures/nlpentity';
 import {
   installNlpValueFixtures,
@@ -26,7 +27,11 @@ import { NlpSampleEntityRepository } from '../repositories/nlp-sample-entity.rep
 import { NlpValueRepository } from '../repositories/nlp-value.repository';
 import { NlpEntity, NlpEntityModel } from '../schemas/nlp-entity.schema';
 import { NlpSampleEntityModel } from '../schemas/nlp-sample-entity.schema';
-import { NlpValue, NlpValueModel } from '../schemas/nlp-value.schema';
+import {
+  NlpValue,
+  NlpValueFull,
+  NlpValueModel,
+} from '../schemas/nlp-value.schema';
 
 import { NlpEntityService } from './nlp-entity.service';
 import { NlpValueService } from './nlp-value.service';
@@ -89,12 +94,17 @@ describe('NlpValueService', () => {
         (acc, curr) => {
           const ValueWithEntities = {
             ...curr,
-            entity: nlpEntityFixtures[parseInt(curr.entity)],
+            entity: nlpEntityFixtures[
+              parseInt(curr.entity)
+            ] as NlpValueFull['entity'],
+            expressions: curr.expressions!,
+            metadata: curr.metadata!,
+            builtin: curr.builtin!,
           };
           acc.push(ValueWithEntities);
           return acc;
         },
-        [],
+        [] as Omit<NlpValueFull, keyof BaseSchema>[],
       );
       expect(result).toEqualPayload(nlpValueFixturesWithEntities);
     });
@@ -130,12 +140,12 @@ describe('NlpValueService', () => {
       const jhonValue = await nlpValueRepository.findOne({ value: 'jhon' });
       const storedValues = [
         {
-          entity: intentEntity.id,
-          value: greetingValue.id,
+          entity: intentEntity!.id,
+          value: greetingValue!.id,
         },
         {
-          entity: firstNameEntity.id,
-          value: jhonValue.id,
+          entity: firstNameEntity!.id,
+          value: jhonValue!.id,
         },
       ];
 
diff --git a/api/src/nlp/services/nlp-value.service.ts b/api/src/nlp/services/nlp-value.service.ts
index d6a51b6d..2d20bde5 100644
--- a/api/src/nlp/services/nlp-value.service.ts
+++ b/api/src/nlp/services/nlp-value.service.ts
@@ -128,7 +128,7 @@ export class NlpValueService extends BaseService<
         if ('start' in e && 'end' in e) {
           const word = sampleText.slice(e.start, e.end);
           return (
-            word !== e.value && vMap[e.value].expressions.indexOf(word) === -1
+            word !== e.value && vMap[e.value].expressions?.indexOf(word) === -1
           );
         }
         return false;
@@ -136,7 +136,7 @@ export class NlpValueService extends BaseService<
       .map((e) => {
         return this.updateOne(vMap[e.value].id, {
           ...vMap[e.value],
-          expressions: vMap[e.value].expressions.concat([
+          expressions: vMap[e.value].expressions?.concat([
             sampleText.slice(e.start, e.end),
           ]),
         } as NlpValueUpdateDto);
@@ -207,9 +207,11 @@ export class NlpValueService extends BaseService<
     const promises = valuesToAdd.map(async (v) => {
       const createdOrFound = await this.findOneOrCreate({ value: v.value }, v);
       // If value is found in database, then update it's synonyms
-      const expressions = createdOrFound.expressions
-        .concat(v.expressions) // Add new synonyms
-        .filter((v, i, a) => a.indexOf(v) === i); // Filter unique values
+      const expressions = v.expressions
+        ? createdOrFound.expressions
+            ?.concat(v.expressions) // Add new synonyms
+            .filter((v, i, a) => a.indexOf(v) === i)
+        : createdOrFound.expressions?.filter((v, i, a) => a.indexOf(v) === i); // Filter unique values
 
       // Update expressions
       const result = await this.updateOne({ value: v.value }, { expressions });
diff --git a/api/src/utils/pipes/search-filter.pipe.ts b/api/src/utils/pipes/search-filter.pipe.ts
index 64221585..3e2c22a8 100644
--- a/api/src/utils/pipes/search-filter.pipe.ts
+++ b/api/src/utils/pipes/search-filter.pipe.ts
@@ -31,7 +31,7 @@ export class SearchFilterPipe<T>
     private readonly props: {
       allowedFields: TFilterNestedKeysOfType<
         T,
-        undefined | string | string[]
+        null | undefined | string | string[]
       >[];
     },
   ) {}
@@ -48,7 +48,10 @@ export class SearchFilterPipe<T>
   private isAllowedField(field: string) {
     if (
       this.props.allowedFields.includes(
-        field as TFilterNestedKeysOfType<T, undefined | string | string[]>,
+        field as TFilterNestedKeysOfType<
+          T,
+          null | undefined | string | string[]
+        >,
       )
     )
       return true;
diff --git a/api/src/utils/test/fixtures/nlpsample.ts b/api/src/utils/test/fixtures/nlpsample.ts
index b62ce7e9..e17bc74c 100644
--- a/api/src/utils/test/fixtures/nlpsample.ts
+++ b/api/src/utils/test/fixtures/nlpsample.ts
@@ -60,7 +60,7 @@ export const installNlpSampleFixtures = async () => {
     nlpSampleFixtures.map((v) => {
       return {
         ...v,
-        language: languages[parseInt(v.language)].id,
+        language: v.language ? languages[parseInt(v.language)].id : null,
       };
     }),
   );