The convenience of having the first email in "claim" the inbox sounds nice, but how do you stop bad actors from claiming other genuine businesses before you've done business with them? ex., one fast food company spamming all of their competitors' names for your accounts?

What's the difficulty in letting someone manually add more domains, or replace the existing domain explicitly without going through a "release inbox, and the next email can claim it again" dance?

I really like this idea, but only in theory right now.

Put the auto rejects into its own list and let the user add it to an existing inbox.

So if I have have the inbox for Facebook.com email, then I notice unsorted messages coming from meta.com, I can merge this into the Facebook inbox. You can probably guess and recommend the correct merge because they’ll inbox in the To: line is already known.

I think if you’re centralizing the data for merging across all users, you can really get smart about recognizing or train an agent on that info.

I don’t think you should ever totally trash an email though. This will lose you users over time. Put them in a list/folder. Similar to how there are Junk and Spam folders where flagged emails get put. The user still gets to have those emails in case they need them or a false flag occurs.

Yeah, that is a good point. We all hate spam, but not receiving something might be worse. We do offer "permanent" inboxes, so that's the easy solution. But if no one will use one-sender or prefix, then that defeats the purpose. Something to think about. In the initial design I had something like that, a list of "blocked" emails. But that just adds more work for people to do...

Tis the nature of communications, email is a chore for sure. It's mighty useful though

You could gather enough data to be able to handle big known players. Randoms get the single claim treatment, and for big services used by a lot of people you could learn the domains and allow adjacent domains.