Jack Dorsey created the early 140-character SMS concept that became Twitter.
Dorsey proposed a service based on short status messages that could be sent through mobile phones. The idea was developed at Odeo in 2006, when text messaging offered a simple way to share brief updates with a group. The original 140-character limit was connected to the 160-character limit used by SMS messages, leaving room for a username and technical formatting.
Dorsey worked with other early contributors, including Biz Stone, Evan Williams, and Noah Glass. Their roles and later relationships became part of Twitter’s complicated founding history, so describing Dorsey as the only creator is an oversimplification.
The 140-character limit eventually changed to 280 characters for most languages in 2017. The early limit therefore describes Twitter’s original design, not the platform’s current posting capacity.