Of course there is.. :) otherwise how we would be able to write plugin :P
You can find major and core API stuffs here http://question2answer.org/developers.php
Welcome to the Q&A site for Question2Answer.
If you have a question about Q2A, please ask here, in English.
To report a bug, please create a new issue on Github or ask a question here with the bug tag.
If you just want to try Q2A, please use the demo site.