Tom Preston-Werner

Thomas Preston-Werner (born May 27, 1979) is an American software developer and billionaire entrepreneur. He is an active contributor within the free and open-source software community, most prominently in the San Francisco Bay Area, where he lives. He is best known as a co-founder and former CEO of GitHub, a web-based Git repository hosting service, which he co-founded in 2008 with Chris Wanstrath and P. J. Hyett. He resigned from GitHub in 2014 when an internal investigation concluded that he and his wife harassed an employee. Preston-Werner is also the creator of the avatar service Gravatar, the TOML configuration file format, the static site generator software Jekyll, and the Semantic Versioning Specification (SemVer). As of 2023, he and his wife have committed to The Giving Pledge—a promise to give away or donate a majority of their wealth to philanthropic causes.