Bridge Base Online

Bridge Base Online (BBO) is the world's largest bridge-playing online platform, with about 10 million monthly visits as of November 2021. Originally created by professional bridge player Fred Gitelman, BBO was first published by Bridge Base, Inc. in 2001 as a Windows-downloadable software offering free online multiplayer bridge rooms for practice and play. Around 2008, BBO was ported to a web application to also support Linux and macOS users, as well as mobile devices.

In 2018, Bridge Base Online was inducted into the American Contract Bridge League's Hall of Fame for its long-term commitment to bridge. As of February 2022, BBO was the only organization ever inducted by the Hall of Fame.

BBO was acquired by the 52 Entertainment Group in December 2018, and Fred Gitelman retired from the company in July 2019.