The Open Source Applications Foundation (OSAF) is a non-profit organization founded in 2002 by Mitch Kapor whose purpose is to effect widespread adoption of free software/open-source software. One significant project undertaken by OSAF was Chandler. As of July, 2006, twenty two people worked full-time, or mostly full-time, on Chandler alongside 4 interns.
Since 2005, OSAF has participated in Google's Summer of Code programs by allowing several interns to work on OSAF's projects during the summer.
OSAF has two other projects under development: Cosmo, a CalDAV server written in Java, and Scooby, an Ajax calendar application that works with Cosmo or another CalDAV server. There are four full time staff combined on these two projects.
The following is a list of some major monetary contributors to OSAF, followed by the amounts in United States dollars.

- Mitch Kapor: 5 million USD
- Andrew W. Mellon Foundation: 98,000 USD
- Andrew W. Mellon Foundation: 1.5 million USD
- Common Solutions Group: 1.25 million USD