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Calling all Office devs: What’s new, different and better with the new app model

Curious about the new app model for Office? This week, Jeremy Chapman is joined by Jeremy Thake to talk about the new app model. They explore the developer options for Office with the building blocks, the object model and application compatibility. Beyond what’s the same, they also explain what is different and demonstrate how new apps are built in Visual Studio.

Prior to joining the Office team at Microsoft, I worked on the Windows team for deployment, imaging and application compatibility. It turns out that application compatibility is one of the biggest stumbling blocks not only for Windows, but also Office and pretty much anything on the desktop and even SharePoint or in some cases Exchange. This week, I’m joined by Jeremy Thake to present the new app model along with core concepts of application compatibility with the old models for all these platforms to explain what is the same, but then we explain what is different with the new app model and what gets better.

If you’re a developer working on or managing add-ins for Office clients, you might be pleasantly surprised to know the object model is virtually unchanged compared to Office 2010 and the object model will remain very static for Office versions to come. So existing add-ins still work and will continue to work even as clients evolve. Why? The new app model is where net new investment is being made and will be made in the future the old model is in sustain mode – and the new forms of extensibility span Office/SharePoint/Exchange workloads with a unified model.

That is great news for those wanting to keep their existing apps working, but if you want to target new on-premises or Office 365 environments, Office Online, SharePoint, Exchange, Windows or non-Windows platforms the new app model will help and its consistent across client and browser experiences. A fundamental difference making this possible is that code runs off the server or client consuming the app content. If you watched the show on mail apps and OWA for Devices with Jason Henderson a few weeks back, you’ll remember that an app written once can be used in Office rich clients, Outlook in the browser, and OWA for Devices (iPhone, iPad, Android Phone) all with the same code running against the Exchange service and off the Exchange server. This means you get broader reach beyond Win32 using the new app model and since the new app model uses HTML5 and JavaScript at the core, more people have the skills to develop these apps.

Beyond those advantages, there are a few more:

1. Developer environment

You don’t need to use that huge developer rig loaded with virtual machines to develop and test your apps.  If you have MSDN, you will have Azure credits and an Office 365 account so its easy to get started. Visual Studio now has integrated experiences to build apps and test them against a running Office 365 environment.

2. Developer Experience

The new app model is consistent across the Office, SharePoint and Exchange stack – whether in Office 365 or on premises. You can share the same service tie-ins across the Office 365 workloads. You can also use the development tools you’re most comfortable with to author and edit HTML and JavaScript.

3. Platform Resilience

The new de-coupled model means that it’s easier to upgrade Office, SharePoint or Exchange without impacting appcompat. In fact, you can update the application running off the consuming clients and those consuming clients don’t necessitate updates.  For example, as you add more mail apps, you don’t even need to update OWA for Devices apps on mobile devices, Outlook rich clients or Office Online for users to see the changes.

Jeremy Thake discusses all of this and more on the show and even demonstrates how you can easily develop apps using built-in integration with Visual Studio and Office 365 at about 9 minutes into the video. Of course this just scratches the surface of the new app model. There are lots of great resources out there and more on the way. For more information, check out or previous Garage Series shows:

Jeremy Thake also hosts the Office 365 Developer Podcast Thursdays on the Office Blog and via podcast feeds. If you’re an Office developer, or you specialize in a single workload like SharePoint or an aspiring developer, I’d encourage you to get started and see what you can do across the Office, SharePoint and Exchange stack using the app model.

See you next time!

Jeremy Chapman

More resources

Office 365 Developer Center





Yammer Office 365 Technical Network

O365 Dev Podcast

O365 Dev Apps Model

O365 Dev Tools

O365 Dev APIs

O365 Dev Migration to App Model

O365 Dev Links



Garage Series Video Channel

Garage Series Season 1 Blog Archive

Follow @OfficeGarage on Twitter

Office 365 Garage Series Apps for Windows Phone and Windows 8


About the Garage Series hosts

By day, Jeremy Chapman works at Microsoft, responsible for optimizing the future of Office client and service delivery as the senior deployment lead. Jeremy’s background in application compatibility, building deployment automation tools and infrastructure reference architectures has been fundamental to the prioritization of new Office enterprise features such as the latest Click-to-Run install. By night, he is a car modding fanatic and serial linguist. Jeremy Thake has been a SharePoint MVP since 2009 and recently joined Microsoft on the apps for Office and extensibility team in Office. Outside of work he’s an avid cyclist, roller hockey player, and huge fan of the NFL and NHL.