Retrofit 2 - Dynamic URL

I think you are using it in wrong way. Here is an excerpt from the changelog:

New: @Url parameter annotation allows passing a complete URL for an endpoint.

So your interface should be like this:

public interface APIService {
    @GET
    Call<Users> getUsers(@Url String url);
}

I wanted to replace only a part of the url, and with this solution, I don't have to pass the whole url, just the dynamic part:

public interface APIService {

  @GET("users/{user_id}/playlists")
  Call<List<Playlist> getUserPlaylists(@Path(value = "user_id", encoded = true) String userId);
}

You can use the encoded flag on the @Path annotation:

public interface APIService {
  @GET("{fullUrl}")
  Call<Users> getUsers(@Path(value = "fullUrl", encoded = true) String fullUrl);
}

• This will prevent the replacement of / with %2F.
• It will not save you from ? being replaced by %3F, however, so you still can't pass in dynamic query strings.

As of Retrofit 2.0.0-beta2, if you have a service responding JSON from this URL : http://myhost/mypath

The following is not working :

public interface ClientService {
    @GET("")
    Call<List<Client>> getClientList();
}

Retrofit retrofit = new Retrofit.Builder()
    .baseUrl("http://myhost/mypath")
    .addConverterFactory(GsonConverterFactory.create())
    .build();

ClientService service = retrofit.create(ClientService.class);

Response<List<Client>> response = service.getClientList().execute();

But this is ok :

public interface ClientService {
    @GET
    Call<List<Client>> getClientList(@Url String anEmptyString);
}

Retrofit retrofit = new Retrofit.Builder()
    .baseUrl("http://myhost/mypath")
    .addConverterFactory(GsonConverterFactory.create())
    .build();

ClientService service = retrofit.create(ClientService.class);

Response<List<Client>> response = service.getClientList("").execute();