What is this site?

HTML5Labs is where Microsoft prototypes early and unstable specifications from web standards bodies such as W3C. Sharing these prototypes helps us have informed discussions with developer communities, and enables us to provide better feedback on draft specifications based on this implementation experience. To find out more about HTML5Labs, read the blog by Jean Paoli, President, Microsoft Open Technologies, Inc.

Important Note: This feature is now available in Internet Explorer 10 that is part of Windows 8. The prototype that had been developed for previous versions of IE is no longer supported. You can now test WebSockets implementation directly in IE10 without needing to install any sort of plugin or prototype.


WebSockets is a technology designed to simplify much of the complexity around bi-directional, full-duplex communications channels, over a single Transmission Control Protocol (TCP) socket. It can be implemented in web browsers, web servers as well as used by any client or server application. The WebSockets API is currently being standardized by the W3C Web Applications Working Group and the protocol is being standardized by IETF Hypertext Bidirectional (HyBi) Working Group.

For feedback please use this mailing list.

There are 3 samples based on the prototype hosted on Windows Azure:

All samples should work with a variety of browsers but mileage may vary. For feedback use this mailing list.

Samples source code is available here.

W3C provides the following mailing list (W3C WebApps WG DL) for feedback about the WebSockets API Spec.

IETF provides the following mailing list for feedback about the HyBi Protocol.

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