I am looking for help to the same question as in Firebase Email verification not working with ActionCodeSetting
The answer is unfortunately incomplete (to me), and I cannot comment on the original answer as I'm new to SO.
What I'd like to know is whether or not it is required to implement the custom email handler (as per https://firebase.google.com/docs/auth/custom-email-handler) on an external host (as in the guide), or if this can be done on iOS client itself?
Thank you