A server that can act as a middle man between a client and a target url. This way, a user can specify what urls to provide mock responses for and also provide the mock response.

Prerequisites

1. Point your app's URL to the mocking server's URL. For example, if my base URL is https://foobar.com then I'll change that to http://ip_address_where_server_is_running:8080. The ip address has mostly been my computer's ip address since that's where I'm running the server.
2. Add my broker_project_token header value for the project which I intend to mock. On android, it should be similar to this if you're using OkHttpClient :

   // An interceptor that adds the header to all my outgoing requests.
   client.newBuilder()
   .addInterceptor {
   it.request().newBuilder()
      .addHeader("broker_project_token", "12345_a_valid_broker_project_token_67890")
      .build().run {
        it.proceed(this)
      }
   }
   

3. For network security on android devices, from Android 9 (API level 28) and above, cleartext support is disabled by default. I had to do this step since I'm running the server on my computer. This stackoverflow answer shows how to do this on android.

Run

shell script cd broker-app .././gradlew run