Refit type-safe REST library

Refit is a library heavily inspired by Square’s Retrofit library, and it turns your REST API into a live interface:

public interface IGitHubApi
{
    [Get("/users/{user}")]
    Task<User> GetUser(string user);
}

The RestService class generates an implementation of IGitHubApi that uses HttpClient to make its calls:

var gitHubApi = RestService.For<IGitHubApi>("https://api.github.com");
var octocat = await gitHubApi.GetUser("octocat");

.NET Core supports registering via HttpClientFactory 

services
    .AddRefitClient<IGitHubApi>()
    .ConfigureHttpClient(c => c.BaseAddress = new Uri("https://api.github.com"));

source