The twice-serving CEO said his departure was due to the company being “ready to move on from its founders.” Dorsey has not announced any future plans.

Twitter CEO Jack Dorsey has resigned from his position at the social media firm after serving for more than six years.

In a Monday tweet to his 5.9 million followers, Dorsey said he had stepped down as the CEO of social media giant Twitter, which he helped co-found in 2006. He announced that the company’s board of directors has appointed Twitter chief technology officer and board member Parag Agrawal to replace Dorsey “starting today.” Dorsey said his decision to step down was based on the board’s approval of Agrawal, board member Bret Taylor agreeing to be the new chair and the opportunities for upward mobility for other Twitter team members.

“I believe it’s really important to give Parag the space he needs to lead,” said Dorsey. “I believe it’s critical a company can stand on its own, free of its founder’s influence or direction.”

Dorsey served as Twitter’s CEO from 2006 to 2008 and later from 2015 following the departure of Dick Costolo. It’s unclear if Dorsey plans to leave the social media firm behind to focus on operations at Square and the platform’s initiative to develop a decentralized Bitcoin (BTC) exchange. 

On Nov. 19, the decentralized exchange project, called tbDEX, released a white paper detailing its plans to create a message protocol designed to facilitate trust relationships without relying on a federation to control access. Though Dorsey has sometimes used his platform to make announcements for the exchange, there are no reports at the time of publication that he plans to get more involved in the project.