Twitter has acquired app tools and testing company Clutch.io. Clutch provides an A/B app testing tool, to compare user response to different versions of apps, and a development framework to help developers build hybrid mobile apps by combining HTML5 and native code. The hosted versions of Clutch’s services will remain available and supported until 1 November, while a new version that can be hosted by developers is in the pipeline. No financial figure was given for the deal.