What Are Microsoft Outlook Add-Ins and How Do They Work?

Is Gmail a Validated Platform?

If you’re familiar with Outlook Add-In development, then you’ve probably used the accountType property of the user’s mailbox at some point to determine feature support.

The values for accountType are:

AccountType ValueExplanation
enterpriseOn-premise exchange
gmailGmail account
office365Microsoft 365 work or school
outlookComOutlook.com account

The unexpected value here is “gmail”. This was originally announced by Microsoft back in 2018, but that initial announcement has long since been removed from their web site. You will find mention of “gmail” in the Add-In documentation occasionally. For example, the page on SSO in Outlook Add-Ins mentions it: “Note: In Outlook, this API is not supported if the add-in is loaded in an Outlook.com or Gmail mailbox.”

There is also some discussion on StackOverflow as to whether or not Gmail is a currently validated platform.

Our Testing

As far as we can tell from testing Add-Ins with Gmail accounts on various platforms, we believe that currently, Gmail Add-Ins are only supported on MacOS. Only on MacOS do the Add-In options appear when a Gmail mailbox is selected. No Add-In options appear on other platforms such as Office 2013, 2016 or 2019.

Our Recommendation

All of this is very confusing! Microsoft may or may not have plans to develop its Gmail capabilities further.

Our recommendation is to provide a graceful fallback for your Add-In so that it still provides some basic, useful functionality when it is run against a Gmail account. We go into fallback strategies and techniques for allowing your Add-In to gracefully fallback on specific platforms on our previous page.

To find out more about the Outlook Add-In development services we can provide at McKenna Consultants, please contact us to speak to one of our specialists and find out how we can help.

Nick McKenna
Since 2004, Nick McKenna, BSc, MBCS Biography has been the CEO of McKenna Consultants. McKenna Consultants is a bespoke software development based in North Yorkshire, specialising in Cloud development, mobile App development, progressive web App development, systems integration and the Internet of Things development. Nick also holds a First Class Degree in Computer Science (BSc) and wrote his first computer program at the age of nine, on a BBC Micro Model B computer. For the last 21 years, Nick has been a professional computer programmer and software architecture. Nick’s technical expertise includes; Net Core, C#, Microsoft Azure, Asp.Net, RESTful web services, eProcurement, Swift, iOS mobile development, Java, Android mobile development, C++, Internet Of Things and more. In addition, Nick is experienced in Agile coaching, training and consultancy, applying modern Agile management techniques to marketing and running McKenna Consultants, as well as the development of software for clients. Nick is a Certified Enterprise Coach (Scrum Alliance), SAFe Program Consultant (SAI), Certified LeSS Practitioner (LeSS) and Certified Scrum@Scale Practitioner. Outside the office, Nick is a professional scuba diver and he holds the rank of Black Belt 5th Dan in Karate.