HTTP client for C# (.NET): top libraries for working with web requests

HTTP client for C# (.NET): overview of the best libraries

When developing modern applications in C# (.NET), there is almost always a need to interact with remote web services and APIs. The base HttpClient class provides all the necessary capabilities, but for complex scenarios (retries, serialization, a convenient fluent interface), the community has created several powerful wrapper libraries. In this article, we will look at four of the most popular HTTP clients for C# (.NET), compare their features, and provide code examples.

1. HttpClient (built-in to .NET)

HttpClient is a standard class from the System.Net.Http namespace, available in all versions of .NET (including .NET Core, .NET 5/6/7/8). It is the foundation upon which all other libraries are built.

Advantages:

• Does not require installing additional packages (included in BCL).
• Full control over the request sending process.
• Support for HTTP/1.1, HTTP/2, HTTP/3.
• Built-in support for gzip/deflate compression.
• Ability to work with streams (streaming).

Disadvantages:

• Requires manual management of retries.
• No built-in JSON serialization/deserialization.
• Verbose code for typical operations.

Usage example:

using System.Net.Http;using System.Text.Json;using System.Threading.Tasks;

public class UserClient{    private readonly HttpClient _httpClient;

    public UserClient()    {        _httpClient = new HttpClient();        _httpClient.BaseAddress = new Uri("https://jsonplaceholder.typicode.com");    }

    public async Task<User> GetUserAsync(int id)    {        var response = await _httpClient.GetAsync($"/users/{id}");        response.EnsureSuccessStatusCode();        var json = await response.Content.ReadAsStringAsync();        return JsonSerializer.Deserialize<User>(json);    }

    public async Task<User> CreateUserAsync(User user)    {        var json = JsonSerializer.Serialize(user);        var content = new StringContent(json, System.Text.Encoding.UTF8, "application/json");        var response = await _httpClient.PostAsync("/users", content);        response.EnsureSuccessStatusCode();        var responseJson = await response.Content.ReadAsStringAsync();        return JsonSerializer.Deserialize<User>(responseJson);    }}

public class User{    public int Id { get; set; }    public string Name { get; set; }    public string Email { get; set; }}

2. RestSharp

RestSharp is one of the oldest and most popular libraries for working with REST APIs. It provides a convenient fluent interface, automatic JSON and XML serialization/deserialization, and built-in error handling.

Advantages:

• Simple and intuitive API.
• Automatic serialization/deserialization.
• Built-in authentication support (Basic, OAuth, JWT).
• Support for file uploads (multipart/form-data).
• Flexible error handling and retry system.

Disadvantages:

• Dependency on an external package (NuGet: RestSharp).
• Overly abstracts HTTP for some scenarios.

Usage example:

using RestSharp;using System.Threading.Tasks;

public class UserClient{    private readonly RestClient _client;

    public UserClient()    {        _client = new RestClient("https://jsonplaceholder.typicode.com");    }

    public async Task<User> GetUserAsync(int id)    {        var request = new RestRequ