The first tweet appeared on Twitter in 2006.
Jack Dorsey posted the first tweet on March 21, 2006, during the early development of the service then known as twttr. The message was an invitation to “set up my twttr,” marking the beginning of a platform built around short public updates.
Twitter was created by Jack Dorsey, Noah Glass, Biz Stone, and Evan Williams. It grew from an internal idea at Odeo, a podcasting company, into a separate social-media service.
The service originally imposed a 140-character limit because messages were designed around mobile SMS constraints. Twitter later doubled the limit for many languages to 280 characters. The first tweet therefore predates the platform’s later scale, branding, and expanded message format.