Provide a way on the Web for FxA relying parties to determine if the user has previously logged into FxA about fxa HOT 7 CLOSED

@andymckay asked for this because it would help with a Payments integration. @bryanbell also suggested it would helpful in IdeaTown.

from fxa.

What are the privacy repercussions of this?

from fxa.

We've already explicitly traded off "leak whether you've got an account with us" in order to get better UX in a variety of places, but those places required you to know the user's email address. IIUC this ask is more "tell whether the current visitor, whoever they are, has a Firefox Account"?

I feel like we must explicitly scope this down to trusted reliers, at least initially. We might even get a lot of mileage out of setting a flag cookie on a shared domain suffix.

@ckarlof can you comment on prioritization/timelines for this?

from fxa.

Agreed that this should be initially limited to internal reliers.

Given that we don't have many Web based reliers at the moment, it's fairly low priority, IMO. At the earliest, probably Q4.

from fxa.

à la Messenger

from fxa.

After discussion is was agreed that the most logical initial internal user of this feature would be a developer of a Mozilla service such as Hello. Hello hasn't currently prioritized this work. I am going to put in a Feature in the Hello Desktop and Fennec clients, link to this issue, and let Romain know, so he can prioritize it up or down.

from fxa.

Exporting these FEATURE cards from Aha has not turned out to be useful in practise, I'm closing them in favour of more direct use of Aha.

This feature lives at: https://mozilla.aha.io/features/FXA-32

And it's references in: https://mozilla.aha.io/features/HELLO-392

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