On what date did Twitter officially launch as a public service?

Twitter officially launched as a public service on July 15, 2006.

The service grew out of Odeo, a podcasting company founded by Evan Williams and Noah Glass. During a company hackathon, Jack Dorsey proposed a short-message platform that could use SMS text messaging to share status updates. The project was initially called twttr, and the first public message was sent in March 2006.

Twitter was incorporated separately from Odeo in April 2007, as its popularity increased. Its early design emphasized brief text updates, originally limited to 140 characters because of the constraints of mobile-phone SMS messages. That limit later became a defining feature of the platform.

The public launch date is sometimes confused with the date of Twitter’s first internal test or its incorporation. Those were earlier milestones, but July 15, 2006 marks the service’s public debut. Twitter later became a major social-media platform and was rebranded as X in 2023.