diff --git a/backend/packages/Upgrade/src/api/DTO/ExperimentDTO.ts b/backend/packages/Upgrade/src/api/DTO/ExperimentDTO.ts
index 5d89189088..ab5d60312f 100644
--- a/backend/packages/Upgrade/src/api/DTO/ExperimentDTO.ts
+++ b/backend/packages/Upgrade/src/api/DTO/ExperimentDTO.ts
@@ -10,6 +10,7 @@ import {
   IsObject,
   IsOptional,
   IsString,
+  IsUUID,
   MaxLength,
   MinLength,
   ValidateIf,
@@ -458,6 +459,12 @@ export class ExperimentDTO {
   public type: EXPERIMENT_TYPE;
 }
 
+export class ExperimentIdValidator {
+  @IsNotEmpty()
+  @IsUUID()
+  public id: string;
+}
+
 export interface ExperimentFile {
   fileName: string;
   fileContent: string;
diff --git a/backend/packages/Upgrade/src/api/controllers/ExperimentClientController.v5.ts b/backend/packages/Upgrade/src/api/controllers/ExperimentClientController.v5.ts
index 6a1363a879..d5dd8b2dde 100644
--- a/backend/packages/Upgrade/src/api/controllers/ExperimentClientController.v5.ts
+++ b/backend/packages/Upgrade/src/api/controllers/ExperimentClientController.v5.ts
@@ -106,7 +106,7 @@ export class ExperimentClientController {
     public metricService: MetricService
   ) {}
 
-  private async checkIfUserExist(
+  public async checkIfUserExist(
     userId: string,
     logger: UpgradeLogger,
     api?: string
diff --git a/backend/packages/Upgrade/src/api/controllers/ExperimentController.ts b/backend/packages/Upgrade/src/api/controllers/ExperimentController.ts
index 8d66e2bd19..597bb45207 100644
--- a/backend/packages/Upgrade/src/api/controllers/ExperimentController.ts
+++ b/backend/packages/Upgrade/src/api/controllers/ExperimentController.ts
@@ -3,7 +3,6 @@ import {
   Get,
   JsonController,
   OnUndefined,
-  Param,
   Post,
   Put,
   Delete,
@@ -17,8 +16,6 @@ import { Experiment } from '../models/Experiment';
 import { ExperimentNotFoundError } from '../errors/ExperimentNotFoundError';
 import { ExperimentService } from '../services/ExperimentService';
 import { ExperimentAssignmentService } from '../services/ExperimentAssignmentService';
-import { SERVER_ERROR } from 'upgrade_types';
-import { isUUID } from 'class-validator';
 import { ExperimentCondition } from '../models/ExperimentCondition';
 import { ExperimentPaginatedParamsValidator } from './validators/ExperimentPaginatedParamsValidator';
 import { UserDTO } from '../DTO/UserDTO';
@@ -28,7 +25,7 @@ import { AppRequest, PaginationResponse } from '../../types';
 import { ExperimentDTO, ExperimentFile, ValidatedExperimentError } from '../DTO/ExperimentDTO';
 import { ExperimentIds } from './validators/ExperimentIdsValidator';
 import { NotFoundException } from '@nestjs/common/exceptions';
-import { IdValidator } from './validators/FeatureFlagValidator';
+import { ExperimentIdValidator } from '../DTO/ExperimentDTO';
 
 interface ExperimentPaginationInfo extends PaginationResponse {
   nodes: Experiment[];
@@ -634,7 +631,7 @@ export class ExperimentController {
    *            description: AuthorizationRequiredError
    */
   @Get()
-  public find(@Req() request: AppRequest): Promise<Experiment[]> {
+  public find(@Req() request: AppRequest): Promise<ExperimentDTO[]> {
     return this.experimentService.find(request.logger);
   }
 
@@ -743,14 +740,6 @@ export class ExperimentController {
     @Req()
     request: AppRequest
   ): Promise<ExperimentPaginationInfo> {
-    if (!paginatedParams) {
-      return Promise.reject(
-        new Error(
-          JSON.stringify({ type: SERVER_ERROR.MISSING_PARAMS, message: ' : paginatedParams should not be null.' })
-        )
-      );
-    }
-
     const [experiments, count] = await Promise.all([
       this.experimentService.findPaginated(
         paginatedParams.skip,
@@ -841,7 +830,10 @@ export class ExperimentController {
    */
   @Get('/single/:id')
   @OnUndefined(ExperimentNotFoundError)
-  public one(@Params({ validate: true }) { id }: IdValidator, @Req() request: AppRequest): Promise<Experiment> {
+  public one(
+    @Params({ validate: true }) { id }: ExperimentIdValidator,
+    @Req() request: AppRequest
+  ): Promise<ExperimentDTO> {
     return this.experimentService.getSingleExperiment(id, request.logger);
   }
 
@@ -920,7 +912,7 @@ export class ExperimentController {
   @Get('/conditions/:id')
   @OnUndefined(ExperimentNotFoundError)
   public async getCondition(
-    @Params({ validate: true }) { id }: IdValidator,
+    @Params({ validate: true }) { id }: ExperimentIdValidator,
     @Req() request: AppRequest
   ): Promise<ExperimentCondition[]> {
     return this.experimentService.getExperimentalConditions(id, request.logger);
@@ -1042,7 +1034,7 @@ export class ExperimentController {
 
   @Delete('/:id')
   public async delete(
-    @Params({ validate: true }) { id }: IdValidator,
+    @Params({ validate: true }) { id }: ExperimentIdValidator,
     @CurrentUser() currentUser: UserDTO,
     @Req() request: AppRequest
   ): Promise<Experiment | undefined> {
@@ -1140,21 +1132,14 @@ export class ExperimentController {
    */
   @Put('/:id')
   public update(
-    @Param('id') id: string,
+    @Params({ validate: true }) { id }: ExperimentIdValidator,
     @Body({ validate: true })
     experiment: ExperimentDTO,
     @CurrentUser() currentUser: UserDTO,
     @Req() request: AppRequest
-  ): Promise<Experiment> {
-    if (!isUUID(id)) {
-      return Promise.reject(
-        new Error(
-          JSON.stringify({ type: SERVER_ERROR.INCORRECT_PARAM_FORMAT, message: ' : id should be of type UUID.' })
-        )
-      );
-    }
+  ): Promise<ExperimentDTO> {
     request.logger.child({ user: currentUser });
-    return this.experimentService.update(experiment, currentUser, request.logger);
+    return this.experimentService.update({ ...experiment, id }, currentUser, request.logger);
   }
 
   /**
@@ -1345,7 +1330,7 @@ export class ExperimentController {
   @Get('/getGroupAssignmentStatus/:id')
   @OnUndefined(ExperimentNotFoundError)
   public async getGroupAssignmentStatus(
-    @Params({ validate: true }) { id }: IdValidator,
+    @Params({ validate: true }) { id }: ExperimentIdValidator,
     @Req() request: AppRequest
   ): Promise<number> | undefined {
     return this.experimentAssignmentService.getGroupAssignmentStatus(id, request.logger);
diff --git a/backend/packages/Upgrade/src/api/controllers/FeatureFlagController.ts b/backend/packages/Upgrade/src/api/controllers/FeatureFlagController.ts
index 9fcd46cc8c..1398cfde4d 100644
--- a/backend/packages/Upgrade/src/api/controllers/FeatureFlagController.ts
+++ b/backend/packages/Upgrade/src/api/controllers/FeatureFlagController.ts
@@ -251,14 +251,6 @@ export class FeatureFlagsController {
     paginatedParams: FeatureFlagPaginatedParamsValidator,
     @Req() request: AppRequest
   ): Promise<FeatureFlagsPaginationInfo> {
-    if (!paginatedParams) {
-      return Promise.reject(
-        new Error(
-          JSON.stringify({ type: SERVER_ERROR.MISSING_PARAMS, message: ' : paginatedParams should not be null.' })
-        )
-      );
-    }
-
     const [featureFlags, count] = await Promise.all([
       this.featureFlagService.findPaginated(
         paginatedParams.skip,
@@ -453,7 +445,7 @@ export class FeatureFlagsController {
     @CurrentUser() currentUser: UserDTO,
     @Req() request: AppRequest
   ): Promise<FeatureFlag> {
-    return this.featureFlagService.update(flag, currentUser, request.logger);
+    return this.featureFlagService.update({ ...flag, id }, currentUser, request.logger);
   }
 
   /**
diff --git a/backend/packages/Upgrade/src/api/controllers/MetricController.ts b/backend/packages/Upgrade/src/api/controllers/MetricController.ts
index e5c1db391d..40f7a019e7 100644
--- a/backend/packages/Upgrade/src/api/controllers/MetricController.ts
+++ b/backend/packages/Upgrade/src/api/controllers/MetricController.ts
@@ -1,8 +1,8 @@
-import { Authorized, JsonController, Get, Delete, Param, Post, Req, Body, Params } from 'routing-controllers';
+import { Authorized, JsonController, Get, Delete, Post, Req, Body, Params } from 'routing-controllers';
 import { MetricService } from '../services/MetricService';
 import { IMetricUnit } from 'upgrade_types';
 import { AppRequest } from '../../types';
-import { MetricKeyValidator, MetricValidator } from './validators/MetricValidator';
+import { ContextValidator, MetricKeyValidator, MetricValidator } from './validators/MetricValidator';
 
 /**
  * @swagger
@@ -56,7 +56,10 @@ export class MetricController {
    *            description: Metrics Context not found
    */
   @Get('/:context')
-  public getMetricsByContext(@Param('context') context: string, @Req() request: AppRequest): Promise<IMetricUnit[]> {
+  public getMetricsByContext(
+    @Params({ validate: true }) { context }: ContextValidator,
+    @Req() request: AppRequest
+  ): Promise<IMetricUnit[]> {
     return this.metricService.getMetricsByContext(context, request.logger);
   }
 
diff --git a/backend/packages/Upgrade/src/api/controllers/PreviewUserController.ts b/backend/packages/Upgrade/src/api/controllers/PreviewUserController.ts
index 5ea80fafb2..0f3cef6491 100644
--- a/backend/packages/Upgrade/src/api/controllers/PreviewUserController.ts
+++ b/backend/packages/Upgrade/src/api/controllers/PreviewUserController.ts
@@ -1,12 +1,22 @@
-import { JsonController, Get, OnUndefined, Param, Post, Put, Body, Authorized, Delete, Req } from 'routing-controllers';
+import {
+  JsonController,
+  Get,
+  OnUndefined,
+  Post,
+  Put,
+  Body,
+  Authorized,
+  Delete,
+  Req,
+  Params,
+} from 'routing-controllers';
 import { UserNotFoundError } from '../errors/UserNotFoundError';
-import { SERVER_ERROR } from 'upgrade_types';
 import { PreviewUserService } from '../services/PreviewUserService';
 import { PreviewUser } from '../models/PreviewUser';
-import { isString } from 'class-validator';
 import { PaginatedParamsValidator } from './validators/PaginatedParamsValidator';
 import { AppRequest, PaginationResponse } from '../../types';
 import { PreviewUserValidator } from './validators/PreviewUserValidator';
+import { IdValidator } from './validators/ExperimentUserValidator';
 
 interface PreviewUserPaginationInfo extends PaginationResponse {
   nodes: PreviewUser[];
@@ -83,14 +93,6 @@ export class PreviewUserController {
     @Body({ validate: true }) paginatedParams: PaginatedParamsValidator,
     @Req() request: AppRequest
   ): Promise<PreviewUserPaginationInfo> {
-    if (!paginatedParams) {
-      return Promise.reject(
-        new Error(
-          JSON.stringify({ type: SERVER_ERROR.MISSING_PARAMS, message: ' : paginatedParams should not be null.' })
-        )
-      );
-    }
-
     const [previewUsers, count] = await Promise.all([
       this.previewUserService.findPaginated(paginatedParams.skip, paginatedParams.take, request.logger),
       this.previewUserService.getTotalCount(request.logger),
@@ -126,14 +128,10 @@ export class PreviewUserController {
    */
   @Get('/:id')
   @OnUndefined(UserNotFoundError)
-  public one(@Param('id') id: string, @Req() request: AppRequest): Promise<PreviewUser | undefined> {
-    if (!isString(id)) {
-      return Promise.reject(
-        new Error(
-          JSON.stringify({ type: SERVER_ERROR.INCORRECT_PARAM_FORMAT, message: ' : id should be of type string.' })
-        )
-      );
-    }
+  public one(
+    @Params({ validate: true }) { id }: IdValidator,
+    @Req() request: AppRequest
+  ): Promise<PreviewUser | undefined> {
     return this.previewUserService.findOne(id, request.logger);
   }
 
@@ -161,7 +159,10 @@ export class PreviewUserController {
    *            description: New ExperimentUser is created
    */
   @Post()
-  public create(@Body({ validate: true }) users: PreviewUserValidator, @Req() request: AppRequest): Promise<PreviewUser> {
+  public create(
+    @Body({ validate: true }) users: PreviewUserValidator,
+    @Req() request: AppRequest
+  ): Promise<PreviewUser> {
     return this.previewUserService.create(users, request.logger);
   }
 
@@ -196,7 +197,7 @@ export class PreviewUserController {
    */
   @Put('/:id')
   public update(
-    @Param('id') id: string,
+    @Params({ validate: true }) { id }: IdValidator,
     @Body({ validate: true }) user: PreviewUserValidator,
     @Req() request: AppRequest
   ): Promise<PreviewUser> {
@@ -224,7 +225,10 @@ export class PreviewUserController {
    *            description: Delete User By Id
    */
   @Delete('/:id')
-  public delete(@Param('id') id: string, @Req() request: AppRequest): Promise<PreviewUser | undefined> {
+  public delete(
+    @Params({ validate: true }) { id }: IdValidator,
+    @Req() request: AppRequest
+  ): Promise<PreviewUser | undefined> {
     return this.previewUserService.delete(id, request.logger);
   }
 
@@ -252,7 +256,10 @@ export class PreviewUserController {
    *            description: Assignment is created
    */
   @Post('/assign')
-  public assign(@Body({ validate: true }) user: PreviewUserValidator, @Req() request: AppRequest): Promise<PreviewUser> {
+  public assign(
+    @Body({ validate: true }) user: PreviewUserValidator,
+    @Req() request: AppRequest
+  ): Promise<PreviewUser> {
     return this.previewUserService.upsertExperimentConditionAssignment(user, request.logger);
   }
 }
diff --git a/backend/packages/Upgrade/src/api/controllers/SegmentController.ts b/backend/packages/Upgrade/src/api/controllers/SegmentController.ts
index 0ed9e31069..d6e47df88c 100644
--- a/backend/packages/Upgrade/src/api/controllers/SegmentController.ts
+++ b/backend/packages/Upgrade/src/api/controllers/SegmentController.ts
@@ -1,24 +1,12 @@
-import {
-  JsonController,
-  Get,
-  Delete,
-  Param,
-  Authorized,
-  Post,
-  Req,
-  Body,
-  QueryParams,
-  Params,
-} from 'routing-controllers';
+import { JsonController, Get, Delete, Authorized, Post, Req, Body, QueryParams, Params } from 'routing-controllers';
 import { SegmentService, SegmentWithStatus } from '../services/SegmentService';
 import { Segment } from '../models/Segment';
-import { SERVER_ERROR } from 'upgrade_types';
-import { isUUID } from 'class-validator';
 import { AppRequest } from '../../types';
 import {
   IdValidator,
   SegmentFile,
   SegmentIds,
+  SegmentIdValidator,
   SegmentImportError,
   SegmentInputValidator,
 } from './validators/SegmentInputValidator';
@@ -383,17 +371,10 @@ export class SegmentController {
    *          description: Internal Server Error, SegmentId is not valid
    */
   @Delete('/:segmentId')
-  public deleteSegment(@Param('segmentId') segmentId: string, @Req() request: AppRequest): Promise<Segment> {
-    if (!segmentId) {
-      return Promise.reject(new Error(SERVER_ERROR.MISSING_PARAMS + ' : segmentId should not be null.'));
-    }
-    if (!isUUID(segmentId)) {
-      return Promise.reject(
-        new Error(
-          JSON.stringify({ type: SERVER_ERROR.INCORRECT_PARAM_FORMAT, message: ' : segmentId should be of type UUID.' })
-        )
-      );
-    }
+  public deleteSegment(
+    @Params({ validate: true }) { segmentId }: SegmentIdValidator,
+    @Req() request: AppRequest
+  ): Promise<Segment> {
     return this.segmentService.deleteSegment(segmentId, request.logger);
   }
 
diff --git a/backend/packages/Upgrade/src/api/controllers/StratificationController.ts b/backend/packages/Upgrade/src/api/controllers/StratificationController.ts
index 751721976e..4de08ff698 100644
--- a/backend/packages/Upgrade/src/api/controllers/StratificationController.ts
+++ b/backend/packages/Upgrade/src/api/controllers/StratificationController.ts
@@ -1,9 +1,12 @@
-import { JsonController, Get, Delete, Param, Authorized, Req, Res, Body, Post } from 'routing-controllers';
-import { SERVER_ERROR } from 'upgrade_types';
+import { JsonController, Get, Delete, Authorized, Req, Res, Body, Post, Params } from 'routing-controllers';
 import { AppRequest } from '../../types';
 import { UserStratificationFactor } from '../models/UserStratificationFactor';
 import { StratificationService } from '../services/StratificationService';
-import { FactorStrata, UploadedFilesArrayValidator } from './validators/StratificationValidator';
+import {
+  FactorStrata,
+  StratificationFactorValidator,
+  UploadedFilesArrayValidator,
+} from './validators/StratificationValidator';
 import { StratificationFactor } from '../models/StratificationFactor';
 import * as express from 'express';
 
@@ -110,16 +113,11 @@ export class StratificationController {
    */
   @Get('/download/:factor')
   public async getStratificationByFactor(
-    @Param('factor') factor: string,
+    @Params({ validate: true }) { factor }: StratificationFactorValidator,
     @Req() request: AppRequest,
     @Res() res: express.Response
   ): Promise<express.Response> {
-    if (!factor) {
-      return Promise.reject(new Error(SERVER_ERROR.MISSING_PARAMS + ' : stratification Factor should not be null.'));
-    }
-
     const csvData = await this.stratificationService.getCSVDataByFactor(factor, request.logger);
-
     // return csv file with appropriate headers to request;
     res.setHeader('Content-Type', 'text/csv; charset=UTF-8');
     res.setHeader('Content-Disposition', `attachment; filename="${factor}.csv"`);
@@ -190,12 +188,9 @@ export class StratificationController {
    */
   @Delete('/:factor')
   public deleteStratification(
-    @Param('factor') stratificationFactor: string,
+    @Params({ validate: true }) { factor }: StratificationFactorValidator,
     @Req() request: AppRequest
   ): Promise<StratificationFactor> {
-    if (!stratificationFactor) {
-      return Promise.reject(new Error(SERVER_ERROR.MISSING_PARAMS + ' : stratification Factor should not be null.'));
-    }
-    return this.stratificationService.deleteStratification(stratificationFactor, request.logger);
+    return this.stratificationService.deleteStratification(factor, request.logger);
   }
 }
diff --git a/backend/packages/Upgrade/src/api/controllers/UserController.ts b/backend/packages/Upgrade/src/api/controllers/UserController.ts
index a14eafe679..8c9046639b 100644
--- a/backend/packages/Upgrade/src/api/controllers/UserController.ts
+++ b/backend/packages/Upgrade/src/api/controllers/UserController.ts
@@ -1,9 +1,8 @@
-import { JsonController, Post, Body, Get, Param, Authorized, Delete, Req } from 'routing-controllers';
+import { JsonController, Post, Body, Get, Authorized, Delete, Req, Params } from 'routing-controllers';
 import { User } from '../models/User';
 import { UserService } from '../services/UserService';
 import { UserDTO } from '../DTO/UserDTO';
-import { UserPaginatedParamsValidator } from './validators/UserPaginatedParamsValidator';
-import { SERVER_ERROR } from 'upgrade_types';
+import { EmailValidator, UserPaginatedParamsValidator } from './validators/UserPaginatedParamsValidator';
 import { AppRequest, PaginationResponse } from '../../types';
 
 interface UserPaginationInfo extends PaginationResponse {
@@ -94,17 +93,6 @@ export class UserController {
     paginatedParams: UserPaginatedParamsValidator,
     @Req() request: AppRequest
   ): Promise<UserPaginationInfo> {
-    if (!paginatedParams || Object.keys(paginatedParams).length === 0) {
-      return Promise.reject(
-        new Error(
-          JSON.stringify({
-            type: SERVER_ERROR.MISSING_PARAMS,
-            message: ' : paginatedParams should not be null or empty object.',
-          })
-        )
-      );
-    }
-
     const [users, count] = await Promise.all([
       this.userService.findPaginated(
         paginatedParams.skip,
@@ -143,7 +131,7 @@ export class UserController {
    *            description: Get User By Email
    */
   @Get('/:email')
-  public getUserByEmail(@Param('email') email: string): Promise<User[]> {
+  public getUserByEmail(@Params({ validate: true }) { email }: EmailValidator): Promise<User[]> {
     return this.userService.getUserByEmail(email);
   }
 
@@ -240,10 +228,7 @@ export class UserController {
    *            description: Delete User By email
    */
   @Delete('/:email')
-  public delete(@Param('email') email: string): Promise<User> {
-    if (!email) {
-      return Promise.reject(new Error(SERVER_ERROR.MISSING_PARAMS + ' : email should not be null.'));
-    }
+  public delete(@Params({ validate: true }) { email }: EmailValidator): Promise<User> {
     return this.userService.deleteUser(email);
   }
 }
diff --git a/backend/packages/Upgrade/src/api/controllers/validators/ExperimentUserValidator.ts b/backend/packages/Upgrade/src/api/controllers/validators/ExperimentUserValidator.ts
index 7e46109908..853723aa2d 100644
--- a/backend/packages/Upgrade/src/api/controllers/validators/ExperimentUserValidator.ts
+++ b/backend/packages/Upgrade/src/api/controllers/validators/ExperimentUserValidator.ts
@@ -88,6 +88,12 @@ export class ExperimentUserValidator extends ExperimentUserValidatorv6 {
   public id: string;
 }
 
+export class IdValidator {
+  @IsNotEmpty()
+  @IsString()
+  public id: string;
+}
+
 export class ExperimentUserArrayValidator {
   @IsNotEmpty()
   @IsArray()
diff --git a/backend/packages/Upgrade/src/api/controllers/validators/FeatureFlagValidator.ts b/backend/packages/Upgrade/src/api/controllers/validators/FeatureFlagValidator.ts
index 15777325cf..ebe4ade568 100644
--- a/backend/packages/Upgrade/src/api/controllers/validators/FeatureFlagValidator.ts
+++ b/backend/packages/Upgrade/src/api/controllers/validators/FeatureFlagValidator.ts
@@ -6,7 +6,7 @@ import { FeatureFlagListValidator } from './FeatureFlagListValidator';
 
 export class FeatureFlagCoreValidation {
   @IsOptional()
-  @IsString()
+  @IsUUID()
   public id: string;
 
   @IsNotEmpty()
@@ -54,16 +54,6 @@ export class FeatureFlagValidation extends FeatureFlagCoreValidation {
   public featureFlagSegmentExclusion?: FeatureFlagListValidator[];
 }
 
-export class UserParamsValidator {
-  @IsNotEmpty()
-  @IsString()
-  public userId: string;
-
-  @IsNotEmpty()
-  @IsString()
-  public context: string;
-}
-
 export class IdValidator {
   @IsNotEmpty()
   @IsUUID()
diff --git a/backend/packages/Upgrade/src/api/controllers/validators/MetricValidator.ts b/backend/packages/Upgrade/src/api/controllers/validators/MetricValidator.ts
index 77604e6cda..ea3f365dbf 100644
--- a/backend/packages/Upgrade/src/api/controllers/validators/MetricValidator.ts
+++ b/backend/packages/Upgrade/src/api/controllers/validators/MetricValidator.ts
@@ -110,3 +110,9 @@ export class MetricKeyValidator {
   @IsString()
   key: string;
 }
+
+export class ContextValidator {
+  @IsNotEmpty()
+  @IsString()
+  context: string;
+}
diff --git a/backend/packages/Upgrade/src/api/controllers/validators/SegmentInputValidator.ts b/backend/packages/Upgrade/src/api/controllers/validators/SegmentInputValidator.ts
index 2ef4584cf7..0cc060847d 100644
--- a/backend/packages/Upgrade/src/api/controllers/validators/SegmentInputValidator.ts
+++ b/backend/packages/Upgrade/src/api/controllers/validators/SegmentInputValidator.ts
@@ -89,3 +89,9 @@ export class SegmentIds {
   @IsUUID('all', { each: true })
   public ids: string[];
 }
+
+export class SegmentIdValidator {
+  @IsNotEmpty()
+  @IsUUID()
+  public segmentId: string;
+}
diff --git a/backend/packages/Upgrade/src/api/controllers/validators/StratificationValidator.ts b/backend/packages/Upgrade/src/api/controllers/validators/StratificationValidator.ts
index 4021c9877e..b0c0c52736 100644
--- a/backend/packages/Upgrade/src/api/controllers/validators/StratificationValidator.ts
+++ b/backend/packages/Upgrade/src/api/controllers/validators/StratificationValidator.ts
@@ -41,3 +41,9 @@ export class UploadedFilesValidator {
   @IsString()
   public file: string;
 }
+
+export class StratificationFactorValidator {
+  @IsNotEmpty()
+  @IsString()
+  public factor: string;
+}
diff --git a/backend/packages/Upgrade/src/api/controllers/validators/UserPaginatedParamsValidator.ts b/backend/packages/Upgrade/src/api/controllers/validators/UserPaginatedParamsValidator.ts
index c9fe00eca9..268cd02ad2 100644
--- a/backend/packages/Upgrade/src/api/controllers/validators/UserPaginatedParamsValidator.ts
+++ b/backend/packages/Upgrade/src/api/controllers/validators/UserPaginatedParamsValidator.ts
@@ -48,3 +48,9 @@ export class UserPaginatedParamsValidator {
   @Type(() => UserSortParamsValidator)
   public sortParams?: UserSortParamsValidator;
 }
+
+export class EmailValidator {
+  @IsNotEmpty()
+  @IsString()
+  public email: string;
+}
diff --git a/backend/packages/Upgrade/src/api/services/ExperimentService.ts b/backend/packages/Upgrade/src/api/services/ExperimentService.ts
index 8fb2ef93b6..be1d6cad01 100644
--- a/backend/packages/Upgrade/src/api/services/ExperimentService.ts
+++ b/backend/packages/Upgrade/src/api/services/ExperimentService.ts
@@ -127,7 +127,7 @@ export class ExperimentService {
     public queryService: QueryService
   ) {}
 
-  public async find(logger?: UpgradeLogger): Promise<Experiment[]> {
+  public async find(logger?: UpgradeLogger): Promise<ExperimentDTO[]> {
     if (logger) {
       logger.info({ message: `Find all experiments` });
     }
@@ -211,7 +211,7 @@ export class ExperimentService {
     });
   }
 
-  public async getSingleExperiment(id: string, logger?: UpgradeLogger): Promise<Experiment | undefined> {
+  public async getSingleExperiment(id: string, logger?: UpgradeLogger): Promise<ExperimentDTO | undefined> {
     const experiment = await this.findOne(id, logger);
     if (experiment) {
       return this.reducedConditionPayload(this.formatingPayload(experiment));
@@ -363,13 +363,11 @@ export class ExperimentService {
     });
   }
 
-  public async update(experiment: ExperimentDTO, currentUser: UserDTO, logger: UpgradeLogger): Promise<Experiment> {
+  public async update(experiment: ExperimentDTO, currentUser: UserDTO, logger: UpgradeLogger): Promise<ExperimentDTO> {
     if (logger) {
       logger.info({ message: `Update the experiment`, details: experiment });
     }
-    return this.reducedConditionPayload(
-      await this.updateExperimentInDB(experiment as ExperimentDTO, currentUser, logger)
-    );
+    return this.reducedConditionPayload(await this.updateExperimentInDB(experiment, currentUser, logger));
   }
 
   public async getExperimentalConditions(experimentId: string, logger: UpgradeLogger): Promise<ExperimentCondition[]> {
diff --git a/backend/packages/Upgrade/src/api/services/FeatureFlagService.ts b/backend/packages/Upgrade/src/api/services/FeatureFlagService.ts
index a152f91b45..561e81f075 100644
--- a/backend/packages/Upgrade/src/api/services/FeatureFlagService.ts
+++ b/backend/packages/Upgrade/src/api/services/FeatureFlagService.ts
@@ -130,7 +130,11 @@ export class FeatureFlagService {
     return featureFlag;
   }
 
-  public async create(flagDTO: FeatureFlagValidation, currentUser: UserDTO, logger: UpgradeLogger): Promise<FeatureFlag> {
+  public async create(
+    flagDTO: FeatureFlagValidation,
+    currentUser: UserDTO,
+    logger: UpgradeLogger
+  ): Promise<FeatureFlag> {
     logger.info({ message: 'Create a new feature flag', details: flagDTO });
     const result = await this.featureFlagRepository.validateUniqueKey(flagDTO);
 
@@ -316,7 +320,11 @@ export class FeatureFlagService {
     return featureFlag;
   }
 
-  public async update(flagDTO: FeatureFlagValidation, currentUser: UserDTO, logger: UpgradeLogger): Promise<FeatureFlag> {
+  public async update(
+    flagDTO: FeatureFlagValidation,
+    currentUser: UserDTO,
+    logger: UpgradeLogger
+  ): Promise<FeatureFlag> {
     logger.info({ message: `Update a Feature Flag => ${flagDTO.toString()}` });
     const result = await this.featureFlagRepository.validateUniqueKey(flagDTO);
 
diff --git a/backend/packages/Upgrade/test/unit/controllers/FeatureFlagController.test.ts b/backend/packages/Upgrade/test/unit/controllers/FeatureFlagController.test.ts
index 327995db78..403fcebf6a 100644
--- a/backend/packages/Upgrade/test/unit/controllers/FeatureFlagController.test.ts
+++ b/backend/packages/Upgrade/test/unit/controllers/FeatureFlagController.test.ts
@@ -45,7 +45,7 @@ describe('Feature Flag Controller Testing', () => {
     return request(app)
       .post('/api/flags')
       .send({
-        id: 'string',
+        id: uuid(),
         name: 'string',
         key: 'string',
         description: 'string',
@@ -95,7 +95,7 @@ describe('Feature Flag Controller Testing', () => {
     return request(app)
       .put('/api/flags/' + uuid())
       .send({
-        id: 'string',
+        id: uuid(),
         name: 'string',
         key: 'string',
         description: 'string',
diff --git a/backend/packages/Upgrade/test/unit/controllers/mocks/ExperimentClientControllerMock.ts b/backend/packages/Upgrade/test/unit/controllers/mocks/ExperimentClientControllerMock.ts
new file mode 100644
index 0000000000..07a29369dc
--- /dev/null
+++ b/backend/packages/Upgrade/test/unit/controllers/mocks/ExperimentClientControllerMock.ts
@@ -0,0 +1,9 @@
+import { Service } from 'typedi';
+import { UpgradeLogger } from '../../../../src/lib/logger/UpgradeLogger';
+
+@Service()
+export default class ExperimentClientControllerMock {
+  public checkIfUserExist(userId: string, take: number, logger: UpgradeLogger, api?: string): Promise<[]> {
+    return Promise.resolve([]);
+  }
+}