Allow iOS users to "Open Firefox" post-verification when verifying in Safari

[shane-tomlinson]

It is not possible to override the default browser on iOS. Whenever a user opens a verification email on the default iOS email client, the link will open in Safari. If the user signed up/in to Fx for iOS then verified in Safari on the same device, we'd like for them to be able to get back to Fx for iOS.

Possible tactic:

One of my London colleagues informed me that in iOS, an can app register itself as the default handler for a given protocol, e.g., moz://. If we know a user was signing up/in to Fx for iOS and the verification link is opened in Safari for iOS, on the /signup_verified page we could show an "Open Firefox" button with a moz:// protocol. Clicking on the button would open Firefox and allow the user to continue where they expect to be.

There are holes in this scheme, like if the user verifies on a 2nd iOS device w/o Firefox. But, really?

[vladikoff]

We already have that handler, it is 'firefox://'

[shane-tomlinson]

We already have that handler, it is 'firefox://'

Even better!

[vladikoff]

I think the main problem with this is "detecting" if Firefox for iOS is installed or not.

This is how Steam deals with not being able to detect if the app is installed on Desktop:

I was proposing to do this for FF iOS but @ryanfeeley softly despises that idea 😸

[vbudhram]

I think it might be possible to have multiple URL schemes in iOS, more is better right :)

[shane-tomlinson]

I think the main problem with this is "detecting" if Firefox for iOS is installed or not.

The button wouldn't be in the verification email, rather on the "signup_verified" or "signin_verified" screen. It seems like a simple heuristic, while not 100% foolproof, could be "close enough":

1. Did the user sign up/in using Fx for iOS?
2. Is the user verifying in Safari for iOS?

If yes to both, "close enough", show the button.

I think it might be possible to have multiple URL schemes in iOS, more is better right :)

This idea was not to show this button in the email, but if a single button in the email can contain both URL scheme's that could work out even better.

[seanmonstar]

It looks like from this document that the Firefox app could register various URLs that it can intercept, which sounds like it could intercept https://accounts.firefox.com/signin_complete or anything else and have Firefox open instead of Safari.