Attacking mobile with a force, Facebook has picked up the three engineering experts behind Pieceable Software, a small I/O Ventures-backed startup that makes a handy developer tool to run and test iOS applications in the browser.

The Facebook-Pieceable deal is of the acqui-hire variety as the social network has only snatched up Pieceable’s team of engineers, and is not purchasing the company, its technology, or its data.

One year-old Pieceable launched the Pieceable Viewer to let iPhone app makers upload their in-progress apps to the web and then share them with testers, colleagues, clients, and so forth. The tool, then, helps creators demonstrate their beta applications with remote audiences without needing a specific iPhone identification number (UDID).

“Since our launch, we’ve served over 800,000 app demos. It’s been an incredibly rewarding experience to become part of the daily workflow for so many companies,” co-founders Fred Potter, Bob Ippolito, and Jameson Hsu wrote in a note to customers Monday announcing the Facebook news.

Pieceable’s three-man engineering team will be joining Facebook’s mobile team, and the iOS app web-testing service will stay operational through the end of the year. An open source version of the Pieceable Viewer will be released at a later date.

“We can’t wait to welcome Fred, Bob and Jameson to Facebook,” a Facebook spokesperson said in a statement to VentureBeat.

Since going public in a rocky début, Facebook has a made a number of strategic deals to beef up its product lineup. The social network purchased mobile gifting app Karma, and then recruited the usability experts behind Bolt Peters. The company is also said to be actively looking at buying Opera for its mobile browser and for its facial recognition technology.

Photo credit: Matt Harnack/Facebook