There are many email clients for mobile platforms, and one of the most recognized ones, Outlook, is about to gain a major functionality.

Microsoft likely knows that email clients can't always be packed with all the features users look for at any given time, so it's leaving that up to third-party developers. Microsoft will now allow others to code extensions, or as it likes to call it, "Add-ins," that integrate with its Outlook for iOS app.

Outlook For iOS Gains Extensions

The first batch of integrations will most likely ring a bell: Evernote, Giphy, Trello, Smartsheet, and more. Several in-house applications are in tow too, such as Microsoft Translator and Dynamics 365.

Enabling Add-ins is drop-dead simple. Install the latest version of Microsoft Outlook for iOS, navigate to the settings menu, and choose the Add-Ins menu. The app will bring up a list of available extensions. Users may add these by hitting the plus sign next to its name.

Once enabled, users can take advantage of the Add-ins when reading an email by tapping the corresponding symbols in the upper right-hand corner. Down the line, Microsoft will enable Add-in functionality in different situations, such as typing up an email.

How Microsoft Outlook Add-Ins Work

Obviously, each Add-in will employ unique behaviors and features: Dynamics 365 will deliver real-time insight about the user's business contacts and their organizations directly to the inbox, cards can be made out of emails via Trello, Microsoft Translator will translate texts in over 60 different languages, and so forth. The feature makes the app its own ecosystem altogether, which is impressive. If more third-party developers code their own Add-ins, Outlook could shape up as the choice mail client for iOS.

Microsoft said that it plans to approve additional Add-ins in the future, and that it's opening development of said extensions to third parties who are interested.

iOS has already enabled app-to-app communication via Extensions, a feature that came with iOS 8. Javier Soltero, corporate VP of Outlook at Microsoft, told Computerworld that in his view, Apple's design follows a series of steps users usually don't follow. To send a photo via email, users need to find it in Photos, open the share sheet, and send the photo to Outlook.

By contrast, Outlook's Add-ins function differently, letting users follow their intent with as few steps as possible.

"You know what you're going to do, you're going to send a message, and what you include in that message is the other consideration," he said.

Add-ins, however, aren't available to everyone just yet, only to Office 365 commercial customers using Outlook for iOS. The feature is slowly rolling out to Outlook.com users, though, and a similar functionality will also arrive on Android soon, alongside MacOS — at least to those who have Outlook 2016 installed.

One key question is, of course, the demand. Developers can keep churning out extension after extension, but if no one finds any use for them, then Add-ins could just end up being largely ignored.

Have you, by any chance, tried Microsoft Outlook's new Add-ins? Tell us the experience so far in the comments section below!