This refers to Proton domain aliases, right? Aliases under our own domains should be unlimited.

Tutanota has this option and why not Proton is limiting users with 5-10-15 aliases?

It would be cool to buy individual alias addresses as a one time purchase.

I would like to be able to give a separate email address to each contact, such that they cannot determine my username from them. For my purposes, it would be okay if these used a combination of random words and numbers, and they could be on a different (sub-)domain. Another service provides throw-away aliases constructed from random words and numbers and at a separate domain from their main email domain. A different service provides "temporary" aliases (called 'slot's in another comment) with user selectable names at a separate sub-domain from their main email domain.

I would like to alter this good proposal a bit: not a paid alias, but rather a 'slot' for an alias, which can be changed.

One main reason why anyone would use an alias at all is that after a while, an email address becomes a target for spammers. If the alias can be discarded or changed, the spam will never reach our mailboxes.

+1. An alias account is pointless if your primary account details (in full form or partial form) appear to the recipient of your email. It's good to be able to use an alias when dealing with businesses which may end up spamming you. So, an alias account lets you know from which recipient of your ermail the spam originated from.

Greetings, when i created the account i wanted my user name to be clear, but if then i would like to send my email with a private name, then the user name must not apear in the automated response with the link to the encrypted mail i could write. thank you for this service it is a good thing!