Outlook.com API brings add-ons from PayPal, Boomerang, Uber and more

Add-ons are a common feature of traditional, offline applications, but they're becoming increasingly popular in online services. Microsoft is the latest to get in on the action, announcing a batch of new add-ons for Outlook.com, including one from PayPal that makes it easy to make payments via email.

The add-ons were made possible when Microsoft launched the Outlook APIs at Build. They can be used by developers to create plugins with HTML, CSS3, and JavaScript. Microsoft is pushing the "write once, run anywhere" nature of the API that means the same plugin can run in Outlook.com, Outlook Web App and the desktop version of Outlook.

Also showcased was a plugin from Boomerang which can be used to schedule the sending of emails, use your inbox as a reminder tool, and share a calendar with others. An Uber add-on is a rather simpler affair, giving users the ability to set up an Uber ride reminder for calendar events. Microsoft says that the API can be used to create "contextual experiences for Outlook.com and Office 365 users that simplify everyday tasks, helping them get more done without the hassle of switching between multiple applications".

In order to get access to the Outlook API, would-be coders need to sign up for a developer account. With around 400 million active users, Outlook.com is something of an untapped market when it comes to monetization by third parties.