Rebex WebSocket

WebSocket library for modern and legacy platforms

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// create an instance of WebSocket client
var client = new WebSocketClient();

// connect to a server

// send a text message

// receive a text message
string response = client.Receive();
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Rebex WebSocket is a WebSocket client library for .NET. It brings TLS 1.2, 1.1, SHA-2, SNI, AES/GCM and other modern security-related features to legacy platforms. Additionally, it supports TLS 1.3 on all mainstream platforms including .NET 3.5 on Windows 7. Rebex WebSocket is designed to offer an easy-to-use API in addition to the advanced .NET ClientWebSocket API.

Why Rebex WebSocket?

Multiplatform WebSocket client

WebSockets are becoming increasingly popular, but support in .NET is far from perfect. Versions of .NET prior to 4.5 don't support WebSockets at all, and even .NET 4.5 only supports WebSockets on Windows 8 or higher.

Rebex WebSocket supports legacy platforms (including .NET Framework 2.0/3.5 and .NET Compact Framework 3.5/3.9) and works on legacy operating systems (Windows Vista SP1, Windows XP SP3, Windows Mobile 5/6, Windows CE, Pocket PC, Windows Embedded Compact). Of course, modern platforms such as .NET Core are supported as well.

TLS 1.2 with SHA-2 certificates on Windows XP and Windows CE; TLS 1.3 on .NET 3.5-5.0 and Windows 7

Rebex WebSocket implements the following modern TLS features:

  • TLS 1.3 on mainstream platforms including .NET 8/7/6/5 (on all platforms) and .NET 3.5-4.8 (on Windows 7, or Windows XP SP3 with plugins)
  • TLS 1.2, 1.1, 1.0 on all platforms (including .NET Compact Framework 3.5/3.9)
  • Elliptic Curve DSA and Elliptic Curve Diffie-Hellman ciphers (requires a plugin on some platforms)
  • AES/GCM ciphers
  • ChaCha20/Poly1305 ciphers
  • SHA-2 certificates
  • SHA-2 hashing algorithms
  • Server Name Indication (SNI) extension
  • Renegotiation Indication extension
  • Support for legacy SSL 3.0 protocol
And more...



8, 7, 6, 5

.NET Framework

3.5 SP1, 4.0-4.8.1

.NET Core



6.0 or higher


13.10 or later


10.1 or later

Learn more about supported standards and platforms.

Legacy platforms

(not included in standard product packages - see more)


.NET Compact Framework


.NET Framework