Office Mobile Apps to Gain Add-In Capabilities in 2015

Stuck between an overly-long Azure presentation and the hype-worthy Windows segment during the Build 2015 keynote earlier this week, Microsoft’s Office announcements barely registered with many watching the event live or remotely. But don’t mistake this lack of publicity for a lack of news: What Microsoft revealed about Office during Build was in fact quite exciting, especially on mobile.

As a backgrounder, Office on the client-side is a far more diverse family of products than the traditional Office desktop applications like Outlook, Word and Excel that run on the PC and Mac. With this important business, Microsoft is adapting to the mobile first, cloud first world by delivering ever more power Office clients on mobile—in many cases, mobile app versions of traditional Office solutions for iPhone, Android, Windows and Windows Phone and the web—Office Online—and with emerging new clients like Sway.

As you might expect, the Office desktop applications are and will continue to be more powerful and full-featured than the mobile apps, in particular. This is due to their longevity—some Office applications date back 30 years—and the resulting mature feature set. The Office mobile apps, meanwhile, are newer and need to run within the constraints of touch-first devices that typically have fairly small screens. So the trick, to date, has been to imbue the Office mobile apps with the right amount of functionality, both in what people expect and in what is possible on such devices.

Despite this, it’s only a matter of time before the Office mobile (and web) apps become the mainstream ways in which customers—both consumers and businesses alike—interface with Office. Microsoft realizes this, and is positioning the desktop applications as high-end, command-rich solutions for content creators and other professionals. The simpler Office mobile (and web) apps are for everyone.

If you had asked me a week ago when “then will become now”—that is, when the Office mobile apps would go mainstream and supplant the Office desktop applications—I would have offered a date a few years out. After all, some of the modern mobile clients—in particular the universal app versions for Windows 10 PCs, tablets and phones—won’t even start shipping until later this year. And Microsoft would need time to mature the mobile apps and bring them ever-closer to the functional level of the desktop applications.

One of the key milestones I was waiting for is extensibility. The Office desktop applications—Office 2013 or newer on the PC and Office 2016 or newer on the Mac—support a powerful HTML 5-based add-in model that allows third party developers to extend these applications with new features. These add-ins are provided through the Office Store, and work similarly to add-ins for web browsers. As an example, here is an SAP add-in Microsoft is building for Excel.

Today, the web apps in Office Online also support these add-ins. So that SAP add-in for Microsoft Excel also works in Excel Online. (Add-ins for Microsoft Outlook will also work with Outlook.com soon, Microsoft says.)

So far, the Office mobile apps lack the extensibility capabilities of the Office desktop applications, which makes sense given their more reduced feature set and the limitations of the devices on which they run. So I figured Microsoft would evolve these apps for a few years and then create a trimmed-down extensibility model that made sense on mobile.

That’s not what they’re doing.

Instead, Microsoft isn’t waiting, and it isn’t creating something different for mobile. It is building extensibility into its Office mobile apps this year—starting soon with Excel for iPad—and it is doing so via the exact same add-in model used on the desktop applications. This is far more aggressive than I thought was possible. And it’s exciting because it means that Office is more consistent and powerful for users no matter where they are, or what devices they choose to use. It is what Microsoft CEO Satya Nadella called “moving from Office from us [Microsoft] to Office with partners … Add-ins [now] go anywhere Office goes.”

On that note, here is the same SAP add-in … running in Excel for iPad. (This isn’t yet available, but Microsoft says we will see it in the coming months.)

“This add-in model is a roadmap for how we’re going to do add-ins going forward,” Microsoft director of program management Rob Lefferts said during the Build keynote, as a smiling Mr. Nadella looked on. He then showed off an add-in running in the web version of Sway, which is one of those new Office apps that Microsoft is quickly iterating. Sway will also support the exact same add-in model as the other Office applications and apps.

Seriously, that is amazing.

“We’re establishing Office as the next big developer target,” Mr. Lefferts told me after the keynote. “We need to be where the users are. And we need to be where the developers are, with HTML 5 and JavaScript” (in contrast to the COM-based standalone Office add-ins of the past.

Excel for iPad will be the first Office mobile app to gain the add-in capabilities, but it will be followed in rapid succession by Word and PowerPoint on iPad (“over the summer”), then Android, and then the universal Windows apps. “It’s a rolling thunder release schedule,” he said.

Lefferts also told me that developers can choose which platforms to support with their add-ins and can adapt them to work within the capabilities of various device types. So you can design for a 4-inch phone screen, a 10-inch tablet or an 84-inch Surface Hub. Developers who are interested in this can get started right now by developing add-ins for Office 2013 for Windows: the add-ins work with Word, Excel, Outlook, PowerPoint and Outlook.

“We just want to make it easy for developers to get this done,” he said. “And we’re being really foot forward, open and transparent, and willing to engage with the whole world of partners out there.”

Exciting days.