MediaWiki core will soon have a REST API.
Some details of the route handler interface are in an RFC which is now
in its last call period:
If you have any problems with this interface, please tell us as soon
There is an associated Gerrit topic branch:
Several of the changes are almost ready to merge. We're not merging
the entry point (rest.php) just yet, that is still marked WIP.
-- Tim Starling