Angular 5 Browse app with services (http request) mocked

Wondering if there as way to use mock services (specifically http request) while browsing your app. I know there are ways to mock with protractor but that is not my use case. I want to deploy the app so QA can manually test with the backend mock with all the request.

On idea that comes to mind is providing some type of build flag that uses mock services instead of the real ones.