This is old, I know, but monit has a basic API, found at
There also appears to be a JSON format as well (change format to json from XML). You can parse the XML for everything you need (I've done it in python easily). However, I can't seem to find any documentation on this, so you have to discover what you can.
Some of the m/monit documentation details some of the monit codes, so you should get some help from there.
You can also check out monittr https://github.com/karmi/monittr.
That is a ruby implementation of monitoring multiple monit instances.