Microsoft 365 Office 365 Outlook Add-ins

Office Add-ins community call–October 14, 2020 

October’s call, hosted by David Chesnut, featured the following presenters and topics: 

  • Courtney Owen showed a demonstration of how to register Office Add-ins in Office on the web using URL query parameters. You can effectively sideload add-ins to Office on the web. 
  • Juan Balmori Labra presented recent updates and announcements for Outlook add-ins. He also talked about optional connected experiences. 
  • Keyur Patel presented recent updates and announcements for Excel add-ins. 
  • David Chesnut demonstrated a new PnP article and sample code showing how to open your add-in in Excel from your SaaS web application. 

Watch the call here. 


We welcome you to submit questions and topic suggestions in advance of each call by using our short survey form.   

We’d like to see better parity between the specific host PowerPoint API with the control that was available in VSTO add-ins for PowerPoint. We have an add-in we want to build out in the new web add-in platform, but can’t due to the extremely limited capabilities of the current Office.js API. 

What’s the status on the limited capabilities of the current Office.js API? 

We are building the OfficeJS API surface area for PowerPoint based on the scenarios that we can enable. For example, in the Office Add-ins community call (September 2020) we announced a few new scenarios we will support with new APIs. 

VSTO is a huge API surface, which is why we approach building out the Office JS API based on prioritized scenarios. It is tremendously helpful to understand the scenarios you are trying to unlock and what API’s are needed. That helps us prioritize. Let us know which scenarios you need enabled on our UserVoice page at We are planning to deliver increased API surface area for PowerPoint going forward. 

In Word we have ‘’ and in Excel we have ‘’ – so question is, when will this be implemented in PowerPoint? We are missing a method to close the active document – is this planned and if yes, when will it be released? This is related to both Word, Excel and PowerPoint. 

Please let us know which scenarios you need enabled on our UserVoice page at It helps us prioritize as we plan API development going forward. There are several save and close related requests there you might want to take a look at or upvote. 

BTW: In Excel you can close the workbook using the following code: 

async function run() { 
  return (context) { 
    return context.sync(); 

Are there plans to make it possible to develop Office add-ins using C#? Using Blazor, for example? Blazor runs in a browser and supports JavaScript interop. ( 

We don’t have support for Blazor today as we’re currently focused on JavaScript. Please let us know more about this scenario on our UserVoice page at (There’s actually already a Blazor request there you can upvote.) 

Do we have a list of the benefits of WebView2 vs WebView? 

 A couple things are: 

  • It is available to all versions of Windows. 
  • It uses the Chromium runtime and provides more consistency across browsers. 
  • And one of our favorites is that it brings right-click > Inspect Element to the context menu. 

For more information see the blog, Announcing WebView2 for Office Add-ins Platform 

I’d like to make sure I understand the essence of this blog around the optional connected services and add-ins. Is it the case that with the right Office version now, one can just use centralized deployment and everything works? Is there anything else they need to know or configure? 

The short answer is yes. The feature is currently released for the monthly channel. Semi Annual is in preview on the Semi Annual Channel Insiders Fast, and will be included in the January 2021 Semi Annual Release. 

When can we try out registering Office Add-ins in Office on the web using URL query parameters? 

Please note, that you must have a dev-server running and your project manifest must be served up by the dev-server. You can try this feature in preview on PowerPoint, OneNote, and Word by joining Office insiders.  

How do you unregister an add-in? 

You can unregister them through the add-in UI or by clearing your Application cache in the browser. You can also right-click > remove the add-in command. 

I am experiencing an issue getting the VS Code extension to step into code at a breakpoint. Any advice on troubleshooting that? 

Debugging can be tricky. Often it is a combination of using the right WebView, used OfficeJS version, used Office versions and more. See Test and debug Office Add-ins for more help with various debugging scenarios. 

What is Fast Food version and could you explain a bit more about Inner rings and Outer rings for identifying which version you have installed? 

Courtney meant Insiders Fast. Just go to File > Account and there should be a button to select the channel you need. Look for insiders fast, and then just update Office. You can find more information on the Office insider program at 

My organization is in a GCC High Tenant. This limits the plugins and features available to me as a developer when using the web hosted versions of the Apps. How can I get access to Script Lab/ Edge DevTools without them being available in our tenant? 

You can get your own developer subscription of Microsoft 365 by joining our developer program: We recommend everyone building add-ins join that. It gives you a free, renewable account for development purposes with 25 users. 

Also, add-ins are actually supported in GCC High environments. But, what might not be enabled is the communication that the add-in needs to do with external services. In house developed add-ins should be doable.  

How do I debug event add-ins in Outlook ? 

We are actually adding a feature in the tooling to do this for Outlook on Windows. 

When will you support compose mode in mobile add-ins?  

This is something that is in our backlog and we expect to tackle this soon. 

What is Preview – does that mean available to Office insiders ? 

Yes it’s Office Insiders Fast. There is an Insiders for Semi Annual Channel. Actually the demo was using the Preview for Semi Annual. 

Where can you submit a request for an addition to the JavaScript Excel API (for example, for a feature that was in the C# API)? 

We use UserVoice for this. check out of there is an existing Idea or create a new one at  

Regarding the contextual ribbon tabs, one of the things that we’ve always wanted was the ability to “group” customized tabs the way that Excel does. For example, if you click into an Excel table/ListObject, there are two grouped contextual tabs (Design and Layout). 

Yes! That’s exactly what the contextual ribbon tab APIs are about. We’ll have guidence on how you can try this out in a future community call. 

What’s needed in addition to Contextual Ribbon Tabs is the ability to create checkboxes, radio buttons, separators, and active/inactive elements. in a custom ribbon tab. 

Yes, additional UX controls are also on the backlog. We haven’t started on that specifically, but we hope to bring more flexibility to the commands space. 

If there are any specific controls you’re interested in, please upvote or log a new request on UserVoice as it will help our user experience team prioritize:  

Are there any plans to update the templates for creating Office add-ins using Visual Studio (as opposed to Visual Studio Code / Yeoman) 

We aren’t able to update those templates as frequently. However, there is a new template for Office UI Fabric React for Visual Studio 2019 available here: 

Is there similar functionality like the PnP Open in Excel sample available for PowerPoint also? 

Yes, the same principles to open in Excel also apply to Word and PowerPoint. We wanted to drive focus on Excel in particular because we’re seeing a lot of “Export to CSV” file capabilities, which would definitely benefit from this “Open in Excel” pattern. 

 Is there an example of how to launch a distinct task pane from each ribbon button? 

From your add-in commands, you can use the ShowTaskpane action and point to different URLs to show different task panes. 


From October’s call 

Office Add-ins community call 

Office Add-ins feedback 

The next Office Add-ins community call is on Wednesday, November 11, 2020 at 8:00AM PDT. You can download the calendar invite at 

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