Web-Based Deployment


Seamless Deployment via web-based O365 add-In

Outlook add-ins are different from COM or VSTO add-ins, which are older integrations specific to Outlook running on Windows. Unlike COM add-ins, Outlook add-ins don’t have any code physically installed on the user’s device or Outlook client - each add-in is at heart a small web application, hosted on a server, and behaving much like any application in a browser. The add-on loads and runs in its own secure sandbox. There’s no access to the rest of your system, making it a more secure approach than the old COM add-ins. For an Outlook add-in, Outlook reads the manifest and hooks up the specified controls. When called (via a user-generated event, like opening a new email message), it loads the add-in’s JavaScript and HTML code, which executes in the context of a browser in a sandbox.

Outlook on Windows uses a JavaScript file, while Outlook on the web uses an HTML file that can reference the same JavaScript file. References to both these files are supplied in the Resources node of the manifest (XML) and the Outlook platform ultimately determines whether to use HTML or JavaScript based on the Outlook client.

Per Microsoft’s guidance, our event-based add-in is short-running, lightweight, and as non-invasive as possible. We use the “event.completed method” to signal that our add-in has completed processing the launch event. If, for any reason the add-in has remained open, Outlook automatically ends ait when the user closes the compose window.

Administrative Deployment

Our add-in can eassily be deployed via the Microsoft O365 admin center.

An alternative deployment approach is to use the Centralized Deployment PowerShell cmdlets to manage add-ins.

Additional Information: How to manage add-ins in the admin center.

Install Add-In Directly from the Microsoft AppSource

(more to come)