diff --git a/packages/backend/src/nest/storageServerProxy/storageServerProxy.service.spec.ts b/packages/backend/src/nest/storageServerProxy/storageServerProxy.service.spec.ts
index f61d0eaa35..4187352e26 100644
--- a/packages/backend/src/nest/storageServerProxy/storageServerProxy.service.spec.ts
+++ b/packages/backend/src/nest/storageServerProxy/storageServerProxy.service.spec.ts
@@ -5,6 +5,7 @@ import { ServerStoredCommunityMetadata } from './storageServerProxy.types'
 import { jest } from '@jest/globals'
 import { prepareResponse } from './testUtils'
 import { createLibp2pAddress, getValidInvitationUrlTestData, validInvitationDatav1 } from '@quiet/common'
+import { Response } from 'node-fetch'
 
 const mockFetch = async (responseData: Partial<Response>[]) => {
   /** Mock fetch responses and then initialize nest service */
@@ -16,11 +17,12 @@ const mockFetch = async (responseData: Partial<Response>[]) => {
     mockedFetch.mockResolvedValueOnce(prepareResponse(data))
   }
 
-  global.fetch = mockedFetch
   const module = await Test.createTestingModule({
     imports: [ServerProxyServiceModule],
   }).compile()
-  return module.get<ServerProxyService>(ServerProxyService)
+  const service = module.get<ServerProxyService>(ServerProxyService)
+  service.fetch = mockedFetch
+  return service
 }
 
 describe('Server Proxy Service', () => {
@@ -49,7 +51,7 @@ describe('Server Proxy Service', () => {
     service.setServerAddress('http://whatever')
     const data = await service.downloadData('cid')
     expect(data).toEqual(clientMetadata)
-    expect(global.fetch).toHaveBeenCalledTimes(2)
+    expect(service.fetch).toHaveBeenCalledTimes(2)
   })
 
   it('throws error if downloaded metadata does not have proper schema', async () => {
@@ -74,6 +76,6 @@ describe('Server Proxy Service', () => {
     service.setServerAddress('http://whatever')
     const token = await service.auth()
     expect(token).toEqual(expectedToken)
-    expect(global.fetch).toHaveBeenCalledTimes(1)
+    expect(service.fetch).toHaveBeenCalledTimes(1)
   })
 })
diff --git a/packages/backend/src/nest/storageServerProxy/storageServerProxy.service.ts b/packages/backend/src/nest/storageServerProxy/storageServerProxy.service.ts
index 4a97ade66d..e3c8f8aa90 100644
--- a/packages/backend/src/nest/storageServerProxy/storageServerProxy.service.ts
+++ b/packages/backend/src/nest/storageServerProxy/storageServerProxy.service.ts
@@ -4,7 +4,7 @@ import { ServerStoredCommunityMetadata } from './storageServerProxy.types'
 import fetchRetry, { RequestInitWithRetry } from 'fetch-retry'
 import Logger from '../common/logger'
 import { isServerStoredMetadata } from '../validation/validators'
-import fetch from 'node-fetch'
+import fetch, { Response } from 'node-fetch'
 
 class HTTPResponseError extends Error {
   response: Response
@@ -20,7 +20,7 @@ export class ServerProxyService extends EventEmitter {
   private readonly logger = Logger(ServerProxyService.name)
   _serverAddress: string
   fetch: any
-  fetchConfig: any
+  fetchConfig: RequestInitWithRetry<typeof fetch>
 
   constructor() {
     super()
@@ -85,7 +85,7 @@ export class ServerProxyService extends EventEmitter {
     if (!dataResponse.ok) {
       throw new HTTPResponseError('Failed to download data', dataResponse)
     }
-    const data: ServerStoredCommunityMetadata = await dataResponse.json()
+    const data = (await dataResponse.json()) as ServerStoredCommunityMetadata
     this.validateMetadata(data)
     this.logger('Downloaded data', data)
     return data
diff --git a/packages/backend/src/nest/storageServerProxy/testUtils.ts b/packages/backend/src/nest/storageServerProxy/testUtils.ts
index 710be9b126..ef7c69023a 100644
--- a/packages/backend/src/nest/storageServerProxy/testUtils.ts
+++ b/packages/backend/src/nest/storageServerProxy/testUtils.ts
@@ -1,3 +1,5 @@
+import { Response, Headers } from 'node-fetch'
+
 export const prepareResponse = (responseData: Partial<Response>) => {
   const ok = responseData.status ? responseData.status >= 200 && responseData.status < 300 : false
   const response: Response = {
@@ -8,6 +10,8 @@ export const prepareResponse = (responseData: Partial<Response>) => {
     statusText: '',
     type: 'basic',
     url: '',
+    size: 10,
+    buffer: () => Promise.resolve(Buffer.from('')),
     clone: function (): Response {
       throw new Error('Function not implemented.')
     },