With a blog post, Dropbox today announced that they are partnering with Microsoft to extend integration with Dropbox storage to the Office mobile apps for iOS and Android. “In the next few weeks”, users will be able to open Office documents in Microsoft’s apps directly from the Dropbox app, and Dropbox sync will be bundled into Office for iPad to create, edit, and sync documents across devices. Dropbox will coexist with Microsoft’s own OneDrive service, and users will even be able to browse their Dropbox account and copy shareable links to files without leaving Office for iOS.

From the Dropbox blog:

We know that much of the world relies on a combination of Dropbox and Microsoft Office to get work done. In fact, Dropbox is home to over 35 billion Office documents, spreadsheets, and presentations. That’s why we’re partnering with Microsoft to help you do more on your phones, tablets, and the web. Soon you’ll be able to access your Dropbox directly from Office apps, and edit Office files from the Dropbox app.

Tom Warren writes at The Verge:

“Access to Dropbox content popped as one of the very first [iPad for Office] requests that customers had,” explains Kirk Koenigsbauer, head of Microsoft’s Office Engineering team. “They want access to where their content is. We’re doing it to make sure customers have a great experience.” Although Microsoft has its own OneDrive cloud storage, Dropbox will appear alongside Microsoft’s own service in the Office for iPad apps, allowing users to natively browse, open, and edit Office documents stored on Dropbox from directly within the app.

I find this interesting for a couple of reasons. First, Microsoft was long criticized for ignoring Office on mobile devices, but, under CEO Satya Nadella, they appear to be actively listening to how people want to use Office on the go – Dropbox is an obvious choice for file storage and sharing, but Microsoft still requires an Office 365 subscription to fully use the iOS apps (side note: Word for iPad is a regular fixture of the App Store’s Top Grossing chart).

It’s also notable that Microsoft has chosen to develop their own custom integration rather than simply rely on Apple’s new document provider feature of iOS 8. As you can see from the screenshots, Word for iPad will have a custom Dropbox file browser with support for multiple accounts that doesn’t require you to open a document picker to switch between file storage locations. Given the complexity of sync and the strategic importance of this partnership, it makes sense for Microsoft to control this integration with a custom, full-featured approach.