Postini, Inc.[1] was an e-mail, Web security, and archiving service owned by Google from 2007 until its closure .

It provided cloud computing services for filtering e-mail spam and malware (before it was delivered to a client's mail server), offered optional e-mail archiving, and protected client networks from web-borne malware.

Postini was a startup company founded in 1999 by Shinya Akamine, Gordon Irlam, Brian Maggi, and Scott Petry in Redwood City, California, United States.

[4] By February 2005, it was operating ten U.S. data centers, processing 2.5 billion e-mail messages weekly, and providing anti-spam services for more than 4,200 companies and "6 million end users, including workers at Merrill Lynch, Circuit City, Rayovac, and Hormel Foods, the company that makes Spam, the canned meat product".

[5] On July 9, 2007, Google announced that it had signed a definitive agreement to acquire Postini.