Firebase Dynamic Links Opening all of my domain links in the app

Question

I'm using a custom domain for Firebase Dynamic Links in my Unity app. The domain is in the format https://mywebsite.com/deeplink/

On Android, this all works fine. Going to mywebsite.com by clicking a link in an email or the browser, opens the URL in the browser and mywebsite.com/deeplink opens the app. On iOS, however, both open the app. This includes, most troubling, the mywebsite.com/_/ URL which Firebase uses for its confirm your email and reset password logic.

My app is configured with applinks:mywebsite.com in the associated domains section and the PList has an entry for FirebaseDynamicLinksCustomDomains with an array that has https://mywebsite.com/deeplink as an entry.

mywebsite.com/apple-site-association has this

{"applinks":{"apps":[],"details":[{"appID":"LK3H8YP4D2.com.help.stressfree","paths":["NOT /_/*","/*"]}]}}

Does anyone have an idea why this is happening and how I can get the app to only open URLs at mywebsite.com/deeplink?

Answer 1

The root domain of your custom Dynamic Link mywebsite.com shouldn't be added in the Associated Domains list. That's the reason why mywebsite.com opens the app in iOS.

Only Google-provided domains (*.page.link) should be added in the Associated Domains list.

https://firebase.google.com/docs/dynamic-links/ios/receive#open-dynamic-links-in-your-app