Loren Brichter, the founder of Atebits, the creator of the iPhone app Tweetie and the mastermind behind Twitter for iPhone, has completed his last day at Twitter.

“Today was my last day at Twitter. Taking some time to figure out what’s next. Really proud of the way the team has grown,” Brichter wrote in a tweet posted to Twitter Friday afternoon.

Brichter has been developing Mac applications since 2007. As the founder of Atebits, Brichter developed Tweetie, a popular Twitter client for the iPhone. Twitter acquired Atebits in April 2010. Brichter then went on to spearhead development on Twitter’s iPhone, iPad and Mac applications.

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