Google has acquired Pixate, a maker of software that helps developers build mobile prototypes running on iOS and Android.

Google has beefed up its design team with the acquisition of the app prototyping firm, its second following last year's purchase of RelativeWave, the company behind Form.

"We're thrilled to announce that Pixate has joined Google! Pixate adds to our ongoing effort to develop new design and prototyping tools, including Form 1.3," Google said in an announcement on Wednesday.

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The Y-Combinator-based company Pixate emerged in 2013 as an iOS-only UI design platform, and used an early investment round to expand its reach to Android developers too. Its initial pitch was to bring the rapid iteration of the web to native apps, and reduce the number of hours developers spent in Adobe Photoshop and Xcode.

The company will now join the Google team responsible for Material Design, which has been rolling out to Android and other web products over the past year.

Google describes Pixate as a "visual prototyping platform" for creating complete app prototypes that run natively in iOS and Android, as well as crafting realistic choreographed interactions. It's also used for collaborating across product teams by sharing those experiences on different devices.

Meanwhile, Google's Form 1.3 prototyping kit is iOS only and is aimed at "advanced designers who want to break ground on new types interactions, gestures, and animations on device".

Announcing the move to Google, Pixate CEO and co-founder Paul Colten said his company's software is integral to the workflow of tens of thousands of designers today but with acquisition it plans to reach millions of product teams worldwide.

Fortunately for designers that use Pixate, Google won't be killing off the service. Instead, the OS X and Windows desktop app for creating prototypes, Pixate Studio, will be free while Google encourages designers to move to the Pixate cloud, which will be charged at $5 per designer per month, or $50 per designer per year.

Pixate users who had paid for the studio license will get a $150 credit towards a Pixate cloud account, while the transition to Google will see the removal of the formerly available free cloud level. In its place Google will introduce be a 60-day Pixate cloud trial.

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