Jack Dorsey is stepping down as CEO of Twitter, the company announced Monday. He will be succeeded by CTO Parag Agrawal, effective immediately.

The big picture: Dorsey is also the CEO of financial payments company Square, which he co-founded in 2009, and has become a crypto evangelist in recent years.

• Agrawal's been with Twitter for over a decade. He's led the company's major products efforts, including most recently overseeing Twitter's decentralized social network standard called "Project BlueSky."

Our thought bubble, via Axios' Scott Rosenberg: Twitter's messaging service was Dorsey's idea 15 years ago, and he led the company through a period of endless controversy surrounding former President Trump's use of the social media site as a personal megaphone.

• Today, the service sits at the center of the U.S. news ecosystem and has gathered much of the real-time energy of social media, but Twitter has never achieved anything close to Facebook's financial success or scale.

What he's saying: "There's a lot of talk about the importance of a company being 'founder-led.' Ultimately I believe that's severely limiting and a single point of failure. I've worked hard to ensure this company can break away from its founding and founders. There are 3 reasons I believe now is the right time" to leave, Dorsey said.

• "The first is Parag becoming our CEO," Dorsey added. "He's been my choice for some time given how deeply he understands the company and its needs ... My trust in him as our CEO is bone deep."
• "The second is Bret Taylor agreeing to become our board chair. I asked Bret to join our board when I became CEO, and he's been excellent in every way ... Having Bret in this leadership role gives me a lot of confidence in the strength of our board going forward."
• "The third is all of you," Dorsey said, addressing Twitter users. "All of you have the potential to change the course of this company for the better."

Background: Dorsey created Twitter alongside Noah Glass, Biz Stone and Evan Williams in 2006 and launched the platform in July of that year.

• Dorsey's first stint as chief executive ended in 2008 after being pushed out by Twitter's board. He returned to the role in 2015 when former CEO Dick Costolo left the company.
• The platform said it had 211 million daily active users last quarter.

What's next: Dorsey said he will serve on Twitter's board through his term, which ends around May, "to help Parag and Bret with the transition."

• He said he will not stay with Twitter after that "to give Parag the space he needs to leave," adding, "I believe it's critical a company can stand on its own, free of its founder's influence or direction."

Go deeper: Dorsey pushes back vs. "founder-led" companies in resignation letter