A slack clone in 10K: Taut
by Max McDonnell
Taut is a Slack clone in 10K of js/css/html that works well in all modern browsers and is functional without clientside javascript. The contest specifies that the 10K limitation just applies to files delivered to the browser, but I enjoyed the constraint of keeping the server code dependency-free and within the size constraint as well.
View the source of this project on GitHub: https://github.com/maxmcd/taut