The Hudson API provides you to communicate with its basic functionalities via REST.
You can use the API with
- XML
- JSON with JSONP support
- Python
to do things like
- retrieve information from Hudson for programmatic consumption
- trigger a new build
- create/copy jobs
Just try it on your houdson server e.g. http://yourhudsonserver/api/ or http://yourhudsonserver/job/foo/lastSuccessfulBuild/api/
For further documentation have a look at the Hudson Remote access API.