diff --git a/src/app.ts b/src/app.ts
index 032ba76..eff3621 100644
--- a/src/app.ts
+++ b/src/app.ts
@@ -16,6 +16,7 @@ import {
   getConfigService,
   ProjectController,
   SubscriptionController,
+  TenderlyController,
   UserController,
 } from './modules';
 
@@ -81,6 +82,7 @@ useExpressServer(app, {
     ProjectController,
     SubscriptionController,
     ContractController,
+    TenderlyController,
   ],
   middlewares: [AppErrorHandler, AuthMiddleware],
 });
diff --git a/src/middleware/errors.ts b/src/middleware/errors.ts
index b3c855f..d7287bf 100644
--- a/src/middleware/errors.ts
+++ b/src/middleware/errors.ts
@@ -6,6 +6,8 @@ import { Service } from 'typedi';
 
 import { getGlobalLogger } from '@bonadocs/di';
 
+import { ApplicationError } from '../modules/errors';
+
 @Service()
 @Middleware({ type: 'after' })
 export default class AppErrorHandler implements ExpressErrorMiddlewareInterface {
@@ -15,6 +17,14 @@ export default class AppErrorHandler implements ExpressErrorMiddlewareInterface
       return;
     }
 
+    if (error instanceof ApplicationError) {
+      response.status(error.statusCode).json({
+        status: error.errorCode,
+        message: error.userFriendlyMessage,
+      });
+      return;
+    }
+
     if ((<Error>error).name === 'PayloadTooLargeError') {
       response.status(StatusCodes.REQUEST_TOO_LONG).json({
         status: 'failed',
diff --git a/src/modules/auth/auth.service.ts b/src/modules/auth/auth.service.ts
index b56b2f2..c252857 100644
--- a/src/modules/auth/auth.service.ts
+++ b/src/modules/auth/auth.service.ts
@@ -53,7 +53,7 @@ export class AuthService {
         userFriendlyMessage: 'Please check your credentials and try again',
       });
     }
-    const user = await this.userRepository.findUserByAuth(request.authSource, authUserId, null);
+    const user = await this.userRepository.findUserByAuth(request.authSource, authUserId);
     if (!user) {
       throw new ApplicationError({
         logger: this.logger,
diff --git a/src/modules/auth/firebase/index.ts b/src/modules/auth/firebase/index.ts
index e73c57a..2d9bacc 100644
--- a/src/modules/auth/firebase/index.ts
+++ b/src/modules/auth/firebase/index.ts
@@ -2,7 +2,7 @@ import crypto, { createHash } from 'crypto';
 
 import { Inject, Service } from 'typedi';
 
-import { ServiceConfiguration } from '../../configuration/config.interface';
+import { GCP } from '../../configuration/config.interface';
 import { ConfigService } from '../../configuration/config.service';
 
 let keysCache: { keys: Record<string, string>; expiry: number } | null = null;
@@ -60,8 +60,7 @@ export class FirebaseJWTProvider {
         return false;
       }
 
-      const gcpProjectId =
-        this.configService.getTransformed<ServiceConfiguration>('gcp').gcp.projectId;
+      const gcpProjectId = this.configService.getTransformed<GCP>('gcp').projectId;
 
       const nowSeconds = Date.now() / 1000;
       if (
diff --git a/src/modules/configuration/config.interface.ts b/src/modules/configuration/config.interface.ts
index 7519085..fcfe3de 100644
--- a/src/modules/configuration/config.interface.ts
+++ b/src/modules/configuration/config.interface.ts
@@ -23,3 +23,30 @@ export type ServiceConfiguration = {
     metaBucket: string;
   };
 };
+
+export type GCP = {
+  projectId: string;
+  collectionsBucket: string;
+  abisBucket: string;
+  automergeBucket: string;
+  metaBucket: string;
+};
+
+export type MailGun = {
+  apiKey: string;
+  domain: string;
+  defaultSender: {
+    name: string;
+    email: string;
+  };
+};
+
+export type Blockscan = {
+  etherscan: Record<string, string>;
+};
+
+export type Tenderly = {
+  accessKey: string;
+  username: string;
+  project: string;
+};
diff --git a/src/modules/connection/dbcontext.ts b/src/modules/connection/dbcontext.ts
index 922be77..ac72022 100644
--- a/src/modules/connection/dbcontext.ts
+++ b/src/modules/connection/dbcontext.ts
@@ -43,12 +43,13 @@ export function withDbContext<T extends (...args: any[]) => Promise<any>>(
   descriptor: TypedPropertyDescriptor<T>,
 ): TypedPropertyDescriptor<T> {
   const originalMethod = descriptor.value!;
-  return async function wrappedFunction(this: object, ...args: any[]) {
+
+  descriptor.value = async function wrappedFunction(this: object, ...args: any[]) {
     const lastArg = args[args.length - 1] as DbContext | undefined | null;
     const dbContext =
       args.length > 0 && lastArg?.isDbContext === true ? (lastArg as DbContext) : undefined;
 
-    // if the last argument is a DbContext, we don't need to create a new one
+    // If the last argument is a DbContext, we don't need to create a new one
     if (dbContext) {
       return originalMethod.apply(this, args);
     }
@@ -104,5 +105,7 @@ export function withDbContext<T extends (...args: any[]) => Promise<any>>(
       }
       poolClient.release();
     }
-  } as TypedPropertyDescriptor<T>;
+  } as T;
+
+  return descriptor;
 }
diff --git a/src/modules/contract/contract.service.ts b/src/modules/contract/contract.service.ts
index 021e02f..06b77df 100644
--- a/src/modules/contract/contract.service.ts
+++ b/src/modules/contract/contract.service.ts
@@ -5,7 +5,7 @@ import { diConstants } from '@bonadocs/di';
 import { BonadocsLogger } from '@bonadocs/logger';
 
 import { getVerifiedContractABI } from '../blockscan/index';
-import { ServiceConfiguration } from '../configuration/config.interface';
+import { GCP } from '../configuration/config.interface';
 import { ConfigService } from '../configuration/config.service';
 import { ApplicationError, applicationErrorCodes } from '../errors';
 import { EvmContractRepository } from '../repositories/evm-contracts/evm-contracts.repository';
@@ -31,7 +31,7 @@ export class ContractService {
       request.chainId,
       request.address,
     );
-    const gcpConfig = this.configService.getTransformed<ServiceConfiguration>('gcp').gcp;
+    const gcpConfig = this.configService.getTransformed<GCP>('gcp');
     if (abiHash) {
       const abi = await this.storage.downloadFile(gcpConfig.abisBucket, `${abiHash}.json`);
 
diff --git a/src/modules/errors/index.ts b/src/modules/errors/index.ts
index 040e240..ccdd11a 100644
--- a/src/modules/errors/index.ts
+++ b/src/modules/errors/index.ts
@@ -1 +1 @@
-export { ApplicationError, applicationErrorCodes } from './ApplicationError';
+export * from './ApplicationError';
diff --git a/src/modules/index.ts b/src/modules/index.ts
index a9118ae..2a78748 100644
--- a/src/modules/index.ts
+++ b/src/modules/index.ts
@@ -5,3 +5,4 @@ export * from './project';
 export * from './user';
 export * from './contract';
 export * from './subscription';
+export * from './tenderly';
diff --git a/src/modules/mailing/mailgun.ts b/src/modules/mailing/mailgun.ts
index 51ffe18..9b4d00e 100644
--- a/src/modules/mailing/mailgun.ts
+++ b/src/modules/mailing/mailgun.ts
@@ -5,7 +5,7 @@ import { Inject, Service } from 'typedi';
 import { diConstants } from '@bonadocs/di';
 import { BonadocsLogger } from '@bonadocs/logger';
 
-import { ServiceConfiguration } from '../configuration/config.interface';
+import { MailGun } from '../configuration/config.interface';
 import { ConfigService } from '../configuration/config.service';
 
 import { MailError, MailSender, SenderConfig, SendOptions } from './types';
@@ -45,14 +45,11 @@ export class MailgunSender implements MailSender {
 
   private loadConfig(): MailgunOptions {
     return {
-      domain: this.configService.getTransformed<ServiceConfiguration>('mail').mailgun.domain,
-      apiKey: this.configService.getTransformed<ServiceConfiguration>('mail').mailgun.apiKey,
+      domain: this.configService.getTransformed<MailGun>('mail').domain,
+      apiKey: this.configService.getTransformed<MailGun>('mail').apiKey,
       defaultSender: {
-        email:
-          this.configService.getTransformed<ServiceConfiguration>('mail').mailgun.defaultSender
-            .email,
-        name: this.configService.getTransformed<ServiceConfiguration>('mail').mailgun.defaultSender
-          .name,
+        email: this.configService.getTransformed<MailGun>('mail').defaultSender.email,
+        name: this.configService.getTransformed<MailGun>('mail').defaultSender.name,
       },
     };
   }
diff --git a/src/modules/project/project.service.ts b/src/modules/project/project.service.ts
index 18035b7..5ab89ab 100644
--- a/src/modules/project/project.service.ts
+++ b/src/modules/project/project.service.ts
@@ -7,7 +7,7 @@ import { BonadocsLogger } from '@bonadocs/logger';
 
 import { AuthService } from '../auth/auth.service';
 import { FirebaseJWTProvider } from '../auth/firebase/index';
-import { ServiceConfiguration } from '../configuration/config.interface';
+import { GCP } from '../configuration/config.interface';
 import { ConfigService } from '../configuration/config.service';
 import { ApplicationError, applicationErrorCodes } from '../errors/ApplicationError';
 import { MailgunSender } from '../mailing/mailgun';
@@ -263,8 +263,7 @@ export class ProjectService {
     }
 
     const fileId = randomBytes(16).toString('hex');
-    const bucketName =
-      this.configService.getTransformed<ServiceConfiguration>('gcp').gcp.collectionsBucket;
+    const bucketName = this.configService.getTransformed<GCP>('gcp').collectionsBucket;
     const fileName = `project-${projectId}/${fileId}.json`;
     await this.storage.uploadFile(
       bucketName,
@@ -343,8 +342,7 @@ export class ProjectService {
         logger: this.logger,
       });
     }
-    const bucketName =
-      this.configService.getTransformed<ServiceConfiguration>('gcp').gcp.collectionsBucket;
+    const bucketName = this.configService.getTransformed<GCP>('gcp').collectionsBucket;
     const publicUrl = this.storage.getFilePublicUrl(bucketName, collection.uri);
 
     return {
@@ -373,8 +371,7 @@ export class ProjectService {
       });
     }
 
-    const bucketName =
-      this.configService.getTransformed<ServiceConfiguration>('gcp').gcp.collectionsBucket;
+    const bucketName = this.configService.getTransformed<GCP>('gcp').collectionsBucket;
 
     const fileName = collection?.uri;
     const savedCollectionData = await this.storage.downloadFile(bucketName, fileName);
@@ -410,8 +407,7 @@ export class ProjectService {
       });
     }
 
-    const bucketName =
-      this.configService.getTransformed<ServiceConfiguration>('gcp').gcp.collectionsBucket;
+    const bucketName = this.configService.getTransformed<GCP>('gcp').collectionsBucket;
     const group = FirebaseJWTProvider.getFcmGroupId(projectId, collectionId);
     const fileName = `firebase-device-ids/${group}.json`;
     const existingFile = await this.storage.downloadFile(bucketName, fileName);
@@ -471,8 +467,7 @@ export class ProjectService {
       });
     }
 
-    const bucketName =
-      this.configService.getTransformed<ServiceConfiguration>('gcp').gcp.collectionsBucket;
+    const bucketName = this.configService.getTransformed<GCP>('gcp').collectionsBucket;
     const fileName = collection!.uri;
     await this.storage.configureFileAccess(bucketName, fileName, request.isPublic);
     await this.projectRepository.updateProjectCollection(
diff --git a/src/modules/repositories/evm-contracts/evm-contracts.repository.test.ts b/src/modules/repositories/evm-contracts/evm-contracts.repository.test.ts
index 19eb6f6..930e32c 100644
--- a/src/modules/repositories/evm-contracts/evm-contracts.repository.test.ts
+++ b/src/modules/repositories/evm-contracts/evm-contracts.repository.test.ts
@@ -8,6 +8,9 @@ import { DbContext } from '../../connection/dbcontext';
 import { EvmContractRepository } from './evm-contracts.repository';
 import { queries } from './queries';
 
+jest.mock('../../connection/dbcontext');
+jest.mock('@bonadocs/logger');
+
 describe('EvmContractRepository', () => {
   let evmContractsRepository: EvmContractRepository;
   let context: jest.Mocked<DbContext>;
diff --git a/src/modules/repositories/projects/project.repository.test.ts b/src/modules/repositories/projects/project.repository.test.ts
index 2e5b2f0..f384cf1 100644
--- a/src/modules/repositories/projects/project.repository.test.ts
+++ b/src/modules/repositories/projects/project.repository.test.ts
@@ -12,6 +12,8 @@ import { queries } from './queries';
 import { CreateProjectDto, GenerateApiKeyDto, InviteUserToProjectDto, PlanDto } from './types';
 import { flagsToPermissions, PermissionNames } from './util';
 
+jest.mock('../../connection/dbcontext');
+jest.mock('@bonadocs/logger');
 describe('ProjectRepository', () => {
   let projectRepository: ProjectRepository;
   let context: jest.Mocked<DbContext>;
diff --git a/src/modules/repositories/projects/project.repository.ts b/src/modules/repositories/projects/project.repository.ts
index ed15420..3361d34 100644
--- a/src/modules/repositories/projects/project.repository.ts
+++ b/src/modules/repositories/projects/project.repository.ts
@@ -37,12 +37,10 @@ export class ProjectRepository {
   @withDbContext
   async createProject(
     data: CreateProjectDto,
-    context?: DbContext | null,
+    context: DbContext | null,
   ): Promise<number | undefined> {
     try {
       context?.beginTransaction();
-      // begin and rollback transaction should happen in the service
-
       const createProjectResult = await context?.query({
         text: queries.createProject,
         values: [data.slug, data.name],
diff --git a/src/modules/repositories/users/user.repository.ts b/src/modules/repositories/users/user.repository.ts
index 00f5476..39e10df 100644
--- a/src/modules/repositories/users/user.repository.ts
+++ b/src/modules/repositories/users/user.repository.ts
@@ -119,7 +119,7 @@ export class UserRepository {
   async findUserByAuth(
     authSource: string,
     authId: string,
-    context: DbContext | null = null,
+    context?: DbContext,
   ): Promise<UserData | null> {
     const result = await context?.query({
       text: queries.findUserByAuth,
diff --git a/src/modules/storage/index.ts b/src/modules/storage/index.ts
index abd51d4..3b0f140 100644
--- a/src/modules/storage/index.ts
+++ b/src/modules/storage/index.ts
@@ -4,7 +4,7 @@ import { Inject, Service } from 'typedi';
 import { diConstants } from '@bonadocs/di';
 import { BonadocsLogger } from '@bonadocs/logger';
 
-import { ServiceConfiguration } from '../configuration/config.interface';
+import { GCP } from '../configuration/config.interface';
 import { ConfigService } from '../configuration/config.service';
 
 let storageClient: GCloudStorage | undefined;
@@ -20,8 +20,7 @@ export class Storage {
     @Inject(diConstants.logger) private readonly logger: BonadocsLogger,
     @Inject() private readonly configService: ConfigService,
   ) {
-    this.gcpProjectId =
-      this.configService.getTransformed<ServiceConfiguration>('gcp').gcp.projectId;
+    this.gcpProjectId = this.configService.getTransformed<GCP>('gcp').projectId;
   }
 
   async uploadFile(
diff --git a/src/modules/tenderly/index.ts b/src/modules/tenderly/index.ts
new file mode 100644
index 0000000..1b8443e
--- /dev/null
+++ b/src/modules/tenderly/index.ts
@@ -0,0 +1 @@
+export { TenderlyController } from './tenderly.controller';
diff --git a/src/modules/tenderly/tenderly.controller.ts b/src/modules/tenderly/tenderly.controller.ts
index ffad6db..ecc971a 100644
--- a/src/modules/tenderly/tenderly.controller.ts
+++ b/src/modules/tenderly/tenderly.controller.ts
@@ -10,7 +10,7 @@ import { TenderlyService } from './tenderly.service';
 @Service()
 @JsonController('/tenderly')
 @Authorized()
-export class ProjectController {
+export class TenderlyController {
   constructor(@Inject() private readonly tenderlyService: TenderlyService) {}
 
   @Get('/stimulate')