WatsonWebsocket 4.1.2

dotnet add package WatsonWebsocket --version 4.1.2                
NuGet\Install-Package WatsonWebsocket -Version 4.1.2                
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.
<PackageReference Include="WatsonWebsocket" Version="4.1.2" />                
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add WatsonWebsocket --version 4.1.2                
#r "nuget: WatsonWebsocket, 4.1.2"                
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package.
// Install WatsonWebsocket as a Cake Addin
#addin nuget:?package=WatsonWebsocket&version=4.1.2

// Install WatsonWebsocket as a Cake Tool
#tool nuget:?package=WatsonWebsocket&version=4.1.2                

alt tag

Watson Websocket

NuGet Version NuGet

WatsonWebsocket is the EASIEST and FASTEST way to build client and server applications that rely on messaging using websockets. It's. Really. Easy.

Thanks and Appreciation

Many thanks and much appreciation to those that take the time to make this library better!

@BryanCrotaz @FodderMK @caozero @Danatobob @Data33 @AK5nowman @jjxtra @MartyIX @rajeshdua123 @tersers @MacKey-255 @KRookoo1 @joreg @ilsnk @xbarra @mawkish00 @jlopvet @marco-manfroni-perugiatiming @GiaNTizmO @exergist @ebarale99 @WarstekHUN @Rubidium37 @codengine

Test App

A test project for both client (TestClient) and server (TestServer) are included which will help you understand and exercise the class library.

A test project that spawns a server and client and exchanges messages can be found here: https://github.com/jchristn/watsonwebsockettest

Supported Operating Systems

WatsonWebsocket currently relies on websocket support being present in the underlying operating system. Windows 7 does not support websockets.


SSL is supported in WatsonWebsocket. The constructors for WatsonWsServer and WatsonWsClient accept a bool indicating whether or not SSL should be enabled. Since websockets, and as a byproduct WatsonWebsocket, use HTTPS, they rely on certificates within the certificate store of your operating system. A test certificate is provided in both the TestClient and TestServer projects which can be used for testing purposes. These should NOT be used in production.

For more information on using SSL certificates, please refer to the wiki.

New in v4.0.x

  • Breaking changes
  • Clients now identified by Guid in ClientMetadata
  • ListClients now returns full ClientMetadata
  • Send* methods now take guid as opposed to IpPort
  • Add targeting for .NET 7.0 and .NET Framework 4.8
  • Fix for Blazor WASM, thank you @ebarale99
  • Fix for invalid control characters, thank you @WarstekHUN

Server Example

using WatsonWebsocket;

WatsonWsServer server = new WatsonWsServer("[ip]", port, true|false);
server.ClientConnected += ClientConnected;
server.ClientDisconnected += ClientDisconnected;
server.MessageReceived += MessageReceived; 

static void ClientConnected(object sender, ConnectionEventArgs args) 
    Console.WriteLine("Client connected: " + args.Client.ToString());

static void ClientDisconnected(object sender, DisconnectionEventArgs args) 
    Console.WriteLine("Client disconnected: " + args.Client.ToString());

static void MessageReceived(object sender, MessageReceivedEventArgs args) 
    Console.WriteLine("Message received from " + args.Client.ToString() + ": " + Encoding.UTF8.GetString(args.Data));

Client Example

using WatsonWebsocket;

WatsonWsClient client = new WatsonWsClient("[server ip]", [server port], true|false);
client.ServerConnected += ServerConnected;
client.ServerDisconnected += ServerDisconnected;
client.MessageReceived += MessageReceived; 

static void MessageReceived(object sender, MessageReceivedEventArgs args) 
    Console.WriteLine("Message from server: " + Encoding.UTF8.GetString(args.Data));

static void ServerConnected(object sender, EventArgs args) 
    Console.WriteLine("Server connected");

static void ServerDisconnected(object sender, EventArgs args) 
    Console.WriteLine("Server disconnected");

Client Example using Browser

server = new WatsonWsServer("http://localhost:9000/");
let socket = new WebSocket("ws://localhost:9000/test/");
socket.onopen = function () { console.log("success"); };
socket.onmessage = function (msg) { console.log(msg.data); };
socket.onclose = function () { console.log("closed"); };
// wait a moment
socket.send("Hello, world!");

Accessing from Outside Localhost

When you configure WatsonWebsocket to listen on or localhost, it will only respond to requests received from within the local machine.

To configure access from other nodes outside of localhost, use the following:

  • Specify the exact DNS hostname upon which WatsonWebsocket should listen in the Server constructor. The HOST header on incoming HTTP requests MUST match this value (this is an operating system limitation)
  • If you want to listen on more than one hostname or IP address, use * or +. You MUST:
    • Run WatsonWebsocket as administrator for this to work (this is an operating system limitation)
    • Use the server constructor that takes distinct hostname and port values (not the URI-based constructor)
  • If you want to use a port number less than 1024, you MUST run WatsonWebsocket as administrator (this is an operating system limitation)
  • If you listen on an interface IP address other than, you MAY need to run as administrator (this is operating system dependent)
  • Open a port on your firewall to permit traffic on the TCP port upon which WatsonWebsocket is listening
  • You may have to add URL ACLs, i.e. URL bindings, within the operating system using the netsh command:
    • Check for existing bindings using netsh http show urlacl
    • Add a binding using netsh http add urlacl url=http://[hostname]:[port]/ user=everyone listen=yes
    • Where hostname and port are the values you are using in the constructor
  • If you are using SSL, you will need to install the certificate in the certificate store and retrieve the thumbprint
  • If you're still having problems, please do not hesitate to file an issue here, and I will do my best to help and update the documentation.

Version History

Please refer to CHANGELOG.md for details.

Product Compatible and additional computed target framework versions.
.NET net6.0 is compatible.  net6.0-android was computed.  net6.0-ios was computed.  net6.0-maccatalyst was computed.  net6.0-macos was computed.  net6.0-tvos was computed.  net6.0-windows was computed.  net7.0 is compatible.  net7.0-android was computed.  net7.0-ios was computed.  net7.0-maccatalyst was computed.  net7.0-macos was computed.  net7.0-tvos was computed.  net7.0-windows was computed.  net8.0 is compatible.  net8.0-android was computed.  net8.0-browser was computed.  net8.0-ios was computed.  net8.0-maccatalyst was computed.  net8.0-macos was computed.  net8.0-tvos was computed.  net8.0-windows was computed. 
.NET Framework net462 is compatible.  net463 was computed.  net47 was computed.  net471 was computed.  net472 was computed.  net48 is compatible.  net481 was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.
  • .NETFramework 4.6.2

    • No dependencies.
  • .NETFramework 4.8

    • No dependencies.
  • net6.0

    • No dependencies.
  • net7.0

    • No dependencies.
  • net8.0

    • No dependencies.

NuGet packages (19)

Showing the top 5 NuGet packages that depend on WatsonWebsocket:

Package Downloads

BigQ is a messaging platform using TCP sockets and websockets featuring sync, async, channel, and private communications. This package includes the BigQ client and associated libraries.


BigQ is a messaging platform using TCP sockets and websockets featuring sync, async, channel, and private communications. This package includes the BigQ server and associated libraries.


BigQ is a messaging platform using TCP sockets and websockets featuring sync, async, channel, and private communications.


BigQ is a messaging platform using TCP sockets and websockets featuring sync, async, channel, and private communications. This package includes the BigQ core libraries. Please also download the BigQ.Client or BigQ.Server package as needed.


View.io is currently in BETA. Database models and supporting classes for View.io services.

GitHub repositories (4)

Showing the top 4 popular GitHub repositories that depend on WatsonWebsocket:

Repository Stars
VisualHFT is a cutting-edge GUI platform for market analysis, focusing on real-time visualization of market microstructure. Built with WPF & C#, it displays key metrics like Limit Order Book dynamics and execution quality. Its modular design ensures adaptability for developers and traders, enabling tailored analytical solutions.
Move a .NET Framework/.NET Core app runtime components and dependencies into a sub-directory and make it beauty.
Mod Manager for Mass Effect Original Trilogy and Mass Effect Legendary Edition
A Sons of The Forest Savegame Editor
Version Downloads Last updated
4.1.2 2,437 5/1/2024
4.1.1 4,984 3/10/2024
4.1.0 124 3/7/2024
4.0.11 40,294 6/28/2023
4.0.10 7,827 5/23/2023
4.0.9 879 5/10/2023
4.0.8 2,927 2/24/2023
4.0.6 4,047 1/31/2023
4.0.4 7,889 1/2/2023
4.0.3 471 12/16/2022
4.0.2 302 12/16/2022
4.0.1 1,499 11/22/2022
3.0.2 5,435 10/24/2022
3.0.1 11,118 8/8/2022
2.3.5 4,259 8/8/2022
2.3.4 2,398 7/11/2022
2.3.3 588 7/2/2022 5,237 5/17/2022 8,335 2/7/2022 8,204 11/12/2021
2.3.2 3,335 10/15/2021
2.3.1 2,245 9/21/2021
2.3.0 14,677 4/15/2021 2,963 2/16/2021 403 2/15/2021 491 2/15/2021
2.2.1 443 2/15/2021 4,722 12/26/2020 558 12/17/2020 824 12/15/2020 654 12/7/2020 473 12/4/2020 702 11/16/2020 503 11/16/2020 504 11/16/2020 681 10/20/2020 623 10/14/2020 490 10/14/2020 526 10/14/2020 714 9/18/2020
2.2.0 615 9/10/2020 32,845 5/19/2020 786 5/18/2020
2.1.7 878 5/16/2020
2.1.6 2,691 5/11/2020
2.1.5 3,149 4/6/2020
2.1.4 12,133 3/29/2020
2.1.3 10,025 3/13/2020
2.1.2 961 3/12/2020
2.1.1 637 3/12/2020
2.1.0 547 3/12/2020
2.0.2 44,872 12/9/2019
2.0.1 12,814 9/21/2019
2.0.0 2,203 9/5/2019
1.3.0 1,170 8/28/2019
1.2.7 603 8/23/2019
1.2.6 573 8/22/2019
1.2.5 649 6/13/2019
1.2.4 4,575 3/11/2019
1.2.3 1,087 12/19/2017
1.2.2 935 9/8/2017
1.2.1 949 8/14/2017
1.2.0 969 7/12/2017
1.1.1 968 7/1/2017
1.1.0 935 6/26/2017
1.0.3 2,707 3/10/2017
1.0.2 943 3/10/2017
1.0.1 942 3/10/2017
1.0.0 1,009 3/8/2017

Retarget to include net8.0.