I've built two Google Workspace addons for testing, one in apps script and one using my own backend server returning JSON (per https://developers.google.com/workspace/add-ons/guides/alternate-runtimes)
The one I created in apps script appears in my Gmail iOS app, but the one I created with my own language returning JSON does not.
Does anyone know if I'm doing something wrong or is this a tradeoff of using your own backend server instead of apps script?
Previously, an alternate runtime (utilizing our own language) for the UI Kit on Gmail for iOS was not accessible. However, I wanted to inform you that this feature is now available.
I've received an email from Google recently regarding this. here the email:
Following the roll-out of the new UI Kit for Gmail on Android and others, the UI Kit for Gmail on iOS has just been made available to the members of the Developer Preview Program. In addition, alternate runtime Add-ons are now supported on iOS.
Only the members of the Developer Preview Program see the updated version of add-ons (*allowlisting in this case is done with your email account, not your Google Cloud project). If a colleague of yours is not in the program, they won’t see the change, nor do your customers. Please note that additional style changes might be seen in future due to our effort to adopt the UI to Material 3 guidelines.
As it's currently exclusive to the Developer Preview Program, you can access it by joining here if you haven't already.