Our API directory now includes 88 project management APIs. The newest is the Trajectory API. The most popular, in terms of mashups, is the Basecamp API. We list 14 Basecamp mashups. Below you'll find some more stats from the directory, including the entire list of project management APIs.
TM Forum, a global trade association that focuses on the digital economy, has just announced the launch of the TM Forum API Zone, featuring a suite of REST-based APIs designed to provide management functionality for end-to-end digital services. These new digital services management APIs were tested and integrated into a variety of apps at the 2013 TM Forum Digital Disruption Conference.