Loxifi.CurlImpersonate 1.3.1

Loxifi.CurlImpersonate

A .NET wrapper around curl-impersonate that provides browser fingerprint impersonation for HTTP requests. This library implements an HttpClient-like API for seamless integration with existing .NET code while providing anti-fingerprinting capabilities.

What is curl-impersonate?

curl-impersonate is a special build of curl that can impersonate the four major browsers: Chrome, Firefox, Safari, and Edge. Unlike standard HTTP clients, it mimics the TLS fingerprint, HTTP/2 settings, and headers of real browsers, making it much harder for servers to detect that requests are coming from an automated tool rather than a real browser.

Installation

dotnet add package Loxifi.CurlImpersonate

Or via the NuGet Package Manager:

Install-Package Loxifi.CurlImpersonate

Quick Start

using Loxifi.CurlImpersonate;

// Create a client that impersonates Chrome 131
using var client = new CurlClient(BrowserProfile.Chrome131);

// Make requests just like HttpClient
HttpResponseMessage response = await client.GetAsync("https://example.com");
string content = await response.Content.ReadAsStringAsync();

Features

• HttpClient-compatible API - Familiar methods like GetAsync, PostAsync, SendAsync
• 31 Browser Profiles - Chrome, Firefox, Safari, Edge, and Tor profiles
• Cookie Support - Automatic cookie handling with CookieContainer
• Redirect Control - Follow redirects automatically or inspect 3xx responses directly
• Proxy Support - HTTP/HTTPS proxy with authentication
• SSL Certificate Handling - Includes CA certificate bundle for production use
• Auto-updating Profiles - Code generator tool to pull latest curl-impersonate releases

Usage Examples

Basic GET Request

using var client = new CurlClient(BrowserProfile.Chrome131);

string html = await client.GetStringAsync("https://example.com");

POST Request with JSON

using var client = new CurlClient(BrowserProfile.Firefox135);

var content = new StringContent(
    "{\"username\":\"test\",\"password\":\"secret\"}",
    Encoding.UTF8,
    "application/json"
);

HttpResponseMessage response = await client.PostAsync("https://api.example.com/login", content);

Inspecting Redirect Responses

Redirects are followed automatically by default. Disable automatic redirects to inspect the original status code and Location header:

using var client = new CurlClient(BrowserProfile.Chrome131)
{
    AllowAutoRedirect = false
};

HttpResponseMessage response = await client.GetAsync("https://example.com/redirect");

if (response.StatusCode == HttpStatusCode.Found)
{
    Uri? destination = response.Headers.Location;
}

Custom Headers

using var client = new CurlClient(BrowserProfile.Safari180);

// Add default headers sent with every request
client.DefaultRequestHeaders["Authorization"] = "Bearer your-token";
client.DefaultRequestHeaders["X-Custom-Header"] = "CustomValue";

var response = await client.GetAsync("https://api.example.com/data");

Using Cookies

using var client = new CurlClient(BrowserProfile.Chrome131);

// Add cookies manually
client.CookieContainer.Add(
    new Uri("https://example.com"),
    new Cookie("session", "abc123")
);

// Cookies from responses are automatically stored
await client.GetAsync("https://example.com/login");

// Subsequent requests include stored cookies
await client.GetAsync("https://example.com/dashboard");

// Disable cookie handling if needed
client.UseCookies = false;

Using a Proxy

using var client = new CurlClient(BrowserProfile.Chrome131);

// Simple proxy
client.Proxy = new WebProxy("http://proxy.example.com:8080");

// Proxy with authentication
client.Proxy = new WebProxy("http://proxy.example.com:8080")
{
    Credentials = new NetworkCredential("username", "password")
};

var response = await client.GetAsync("https://example.com");

Base Address

using var client = new CurlClient(BrowserProfile.Chrome131);
client.BaseAddress = new Uri("https://api.example.com");

// Relative URLs are combined with BaseAddress
var users = await client.GetStringAsync("/users");
var posts = await client.GetStringAsync("/posts");

Timeout Configuration

using var client = new CurlClient(BrowserProfile.Chrome131);
client.Timeout = TimeSpan.FromSeconds(60);

Insecure Mode (Skip SSL Verification)

// WARNING: Only use for testing with self-signed certificates
using var client = new CurlClient(BrowserProfile.Chrome131);
client.Insecure = true;

Available Browser Profiles

Chrome

• Chrome99, Chrome99Android
• Chrome100, Chrome101, Chrome104, Chrome107
• Chrome110, Chrome116, Chrome119, Chrome120
• Chrome123, Chrome124, Chrome131, Chrome131Android
• Chrome133a, Chrome136

Firefox

• Firefox133, Firefox135

Safari

• Safari153, Safari155, Safari170
• Safari172iOS, Safari180, Safari180iOS
• Safari184, Safari184iOS, Safari260, Safari260iOS

Edge

• Edge99, Edge101

Tor

• Tor145

API Reference

CurlClient

Updating Browser Profiles

This library includes a code generator tool that automatically pulls the latest curl-impersonate release from GitHub and regenerates the browser profile code.

To update to the latest profiles:

# Windows
Update.bat

# Or manually
dotnet run --project src/Loxifi.CurlImpersonate.CodeGen

This will:

1. Download the latest curl-impersonate release
2. Extract the native binaries and bat files
3. Parse the bat files to extract browser fingerprint settings
4. Generate updated BrowserProfile.cs and BrowserProfileSettings.cs

Platform Support

Currently supports:

• Windows x64 (win-x64)

The native curl-impersonate binaries are included in the NuGet package and automatically copied to the output directory.

How It Works

1. Browser Profile Selection: Each profile contains the exact TLS ciphers, curves, HTTP/2 settings, and headers used by that browser version.

2. curl-impersonate Execution: Requests are executed via the bundled curl-impersonate binary with the appropriate flags.

3. Response Parsing: The curl output is parsed and converted to standard HttpResponseMessage objects.

4. Cookie Management: Cookies are automatically extracted from responses and sent with subsequent requests.

Credits

This project is a .NET wrapper around the excellent curl-impersonate project by lexiforest.

curl-impersonate is a special build of curl that performs TLS and HTTP handshakes identical to real browsers. It is based on:

• curl - The underlying HTTP client
• Modified TLS libraries (BoringSSL/NSS) to mimic browser TLS fingerprints

License

This project is licensed under the MIT License.

curl-impersonate is licensed under the MIT License.

Contributing

Contributions are welcome! Please feel free to submit issues and pull requests.

See Also

• curl-impersonate GitHub
• TLS Fingerprinting
• HTTP/2 Fingerprinting