Since March 10, 2003 - Version 2.1

MSN Messenger Protocol

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This website is intended to be an unofficial guide to the MSN Messenger protocol. It is written primarily for programmers that want to write software that uses the MSN Messenger protocol.

If you're an MSN Messenger or Windows Messenger user, and have a problem with the program on your computer, please look at the links page. This site won't be of any use to you.

If you're a developer who wants to learn how to interact with Microsoft software (for example, where Windows Messenger stores information in the registry), please see the links page for sites with information about this.

If you're a developer who wants to write your own MSN Messenger software, this site will be very helpful to you. However, you may want to look at the projects page before you start - you might be able to pick up a pre-existing project, or use libraries in parts of your program instead of re-inventing the wheel. If you choose to write your own software, you'll need a basic basic knowledge of network programming before reading this site, but nothing more. Some (optional) parts of the Messenger protocol require an understanding of other technologies like HTTP and XML, but you can implement the most important part of the protocol without these.


The website itself was written primarily by Mike Mintz. The content was originally written by Mike Mintz, but the current version of the website has also been greatly contributed to by Andrew Sayers. The information on this site represents the work of a large and vibrant MSN research community, who the authors would like to thank.

More Information

For more information about this website (including contact information), please read the About page.


December 19, 2003

Version 2.1 of this website was officially published today. Older versions are still available, but are now of only historical interest.

Copyright ©2002-2004 to Mike Mintz.