Alchemy Websockets is a C# .NET library that allows a web browser that supports the WebSockets protocol to connect to a server application using a peristant TCP connection. This means that we can employ real-time, stateful communication between web applications and server applications. WebSockets are supported by current versions of Chrome, FireFox, Safari, and Opera and Opera Mobile with special configuration settings set. IE10 will also have WebSockets. Alchemy can run on Mono (which means EC2 is a go) and supports most versions of the protocol, stretching from hybi-00 to the latest (and final) RFC spec.

We (Drew and I and Olivine Labs) had started considering how to use WebSockets for some of the games we were building and planning. At the time, we were thinking about using them for chat for the now-defunct Chrysellia; and we have plans to build a game that uses WebSockets fully as its transport. Our search took us first to socket.io, a Node.js implementation that gave not only WebSockets, but also fallbacks with Comet and Ajax long-polling and other hackish methods of doing socket-like communication.

However, while I, a javascript developer, originally lobbied for Node.js and Socket.io, we decided to move forward with C#. It isn't the new, sexy language, but it is a language that we both know well; and better, we could take advantage of C#'s amazing microthreading. We built the library around this core threading model so that it could very efficiently handle hundreds of thousands of simultaneous connects, disconnects, and messages on a single server. Drew was able to get around 200k live connections on his dev box before he ran out of memory for the clients.

Alchemy also includes a WebSocket client for server intercommunication that uses the latest protocol version rfc6455 to talk to anything else running WebSockets (whether Alchemy or otherwise.)

We'll be putting it up to a big test with a server infrastructure management API that we've called Tiamat and an API command router called Vocale that will be built over the coming months (we plan to MIT / LGPL these as well).