All Nexus functionality is exposed via a RESTful API, the details of this API have been published. This is a work in progress as we continue to add new functionality, but these pages are regularly updated as part of our development process.
Also posted is our up to date product roadmap.
If you have ideas or want to get something added to the map, please join us at #nexus on irc.codehaus.org or Subscribe to our user list and report an issue to our Jira.