Tristan O'Tierney, one of Square's team of co-founders is leaving the mobile payments company after four years.
O'Tierney, who Tweeted about his departure, did not reveal his future plans other than a desire to travel. A former Apple and Yahoo engineer, O'Tierney built Square's iPhone app and was a lead developer for the company's first iPad app, Square Register for in-store payments, and the Pay with Square service.
O'Tierney's the latest in a series of executive departures at Square. Alyssa Cutright, vice president of international and Alex Petrov, vice president of partnerships, both recently left the company; as did Rob von Behren, an engineer who left Square to join Braintree. Square chief operating officer Keith Rabois left the company in January amid a sexual harassment allegation.
Square recently hired Demetrios Marantis, a former Obama administration trade official, to aid its international expansion strategy. It also hired Francoise Brougher, a former Google executive, as business lead.
Square also recently redesigned its Square Wallet mobile payment app