CodeCombat is a multiplayer programming game for learning how to code. See the Archmage (coder) developer wiki for a dev setup guide, extensive documentation, and much more to get started hacking!
It's both a startup and a community project, completely open source under the MIT and Creative Commons licenses. It's the largest open source CoffeeScript project by lines of code, and since it's a game (with really cool tech), it's really fun to hack on. Join us in teaching the world to code! Your contribution will go on to show millions of players how cool programming can be.
Whether you're novice or pro, the CodeCombat team is ready to help you implement your ideas. Reach out on our forum, our issue tracker, or our developer chat room on Slack, or see the docs for more on how to contribute.
Note: the levels on codecombat.com are not open source.
We offer a partner API for SSO, user management, progress data, etc., with API docs here. You'll need client credentials, so get in touch with us if you have a use case for that.
For the very simplest case that can power some data integrations with your CodeCombat account, you can fetch
https://codecombat.com/db/user/your-user-name-or-id to get some user progress stats. For example, Beeminder uses this API to help you commit to learning to code.