Building Robust API Clients with ✅Refit REST Library in C#

Refit is a powerful REST client library for .NET that simplifies building API clients by automatically generating boilerplate code for HTTP requests.

With Refit, developers define API endpoints using C# interfaces, and the library handles the rest, making the client implementation cleaner, more testable, and less error-prone. Let’s walk through how to use Refit to build a robust API client in C#.

Why Use Refit?

• Reduced Boilerplate: No need to manually create HTTP requests.
• Strongly Typed: Compile-time checks for the structure of API requests and responses.
• Easy Integration: Works well with Dependency Injection and popular HTTP clients like HttpClient.
• Testability: Since API clients are defined using interfaces, they can be easily mocked for unit tests.

1. Create a New ASP.NET Web API Project

dotnet new webapi -n RefitRESTLib
cd RefitRESTLib

2. Installing Refit

To get started with Refit, install the NuGet package via the .NET CLI:

dotnet add package Refit.HttpClientFactory --version 7.1.2

Or using the NuGet Package Manager:

NuGet\Install-Package Refit.HttpClientFactory -Version 7.1.2

3. Defining the API Interface

Refit requires you to define your API as an interface with methods representing API calls. Here’s a sample interface for a typical CRUD API:

• [Get], [Post], [Put], and [Delete] are Refit attributes that map HTTP methods to the corresponding API endpoints.