As Facebook struggles to make its mobile experience better--and more profitable--Twitter is making mobile moves of its own. Its latest: "acqhiring" the app-testing start-up Clutch.io. Terms of the deal were not disclosed by either party.

San Francisco-based Clutch announced the deal Monday on its blog.

“Our mission over the last few months has been to help mobile developers iterate fast and grow their user base,” co-founders Eric Florenzano and Eric Maguire wrote. “Now, as part of Twitter’s growth and international team, we’re excited for the opportunity to focus our efforts on Twitter’s product at a large scale.”

Clutch is an A/B testing company that helps developers test the user interfaces of their mobile apps to attract more users. So, for example, a developer might use the data-driven tests to decide whether to make an app's download button blue or green.

For developers, the news wasn't necessarily positive: Twitter confirmed with Wired that it acquired Clutch for its intellectual property. In other words, Clutch's service will shut down on November 1. 

Florenzano and Maguire worked together before Clutch as co-founders of Y Combinator-backed communication application Convore. The duo’s experience with mobile applications should help Twitter produce real-time updates and enhance user experience across all mobile Twitter applications, Wired says. 

Clutch is the seventh acquisition Twitter has made in the last year—the most the company has made in a single year.