Microsoft has today launched Send, an experimental iPhone app that offers a kind of cross between email and instant messaging. Microsoft says that it is designed for “brief, snappy communications” where you want an instant response but also want to retain a record of what was said within Outlook. The app was previously leaked as Flow by Outlook.

Tellingly, Microsoft is launching first for iPhone – ahead of not just Android, but also its own Windows Phone platform … 

While tools like text messaging and IM are great for short messages, you often don’t have your co-worker’s cell phone number or an IM app on your work phone. And we’ve heard loud and clear from people at work, they want all their communications available in Outlook—even if they send them from other apps. This is where Send comes in! Send gives you the simple, quick text message-like experience while allowing you to reach all co-workers and have all of your communications in Outlook for reference later.

The idea that you wouldn’t have a co-worker’s cell number just seems bizarre, but perhaps there’s merit to the idea of a message which distinguishes itself from standard email yet is still archived in Outlook. Microsoft says that Send is different to standard email as it shows only those messages sent using the app itself.

The app is part of the Microsoft Garage program, effectively a beta-test program for experimental software that may or may not become mainstream Microsoft apps – such as the recently-released Tossup.

Send is a free download from the App Store in the U.S. and Canada only at present. It is intended to be used alongside the Office 2016 productivity suite, the latest Mac version of which was officially released earlier this month.