To help you get started, the HipChat team maintains 2 client frameworks which support App extensions. These frameworks make it easy to build an add-on without having to worry about the plumbing:
|Tutorial||Getting started with atlassian-connect-express (Node.js)|
Not using Node or Python and not sure how to get started? These are libraries provided by third-party HipChat hackers to make using API v2 as easy as a function call:
Have a library or plugin that's not listed here? Let us know!