Custom Protocol Links Not Opening in Microsoft Teams Desktop App, But Work in Browser

Question

I have a custom Teams tab where I use window.open() to open a protocol link (example.appserver:start). This works perfectly when running Microsoft Teams in a web browser, but it does not work inside the Microsoft Teams desktop app. However, window.open() does work for regular URLs (e.g., opening a webpage), so it's not being blocked entirely. Has anyone encountered this issue, and is there a workaround to make custom protocol links open in the Teams desktop app?

Answer 1

Microsoft Teams has certain restrictions on custom protocols for security reasons. The content-security-policy does limit which protocols are allowed within the Teams client and we are currently not supporting adding new protocols. In fact, over time we'd much rather shrink it and get to a point where we only render https: content within the Teams client.

Thanks, 

Prasad Das

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