We just deployed the last couple of changes we wanted to do before the “public beta”, the current API docs can be found at:
http://discuss.bitrise.io/t/bitrise-api-v0-1-work-in-progress/1554
Please keep in mind that this is work in progress, new endpoints will be added soon. There are still a couple of technical details we have to talk though, but we think that the base structure of the API is sufficient to build upon.
If you have any questions feel free to ask here, or leave a comment at the API docs topic.