How to make Usernames unique

Hi I was wondering how to make usernames unique or atleast a way to not make it possible to change your username through the API but only the ones with a token so I can do the usernames myself.

What do you mean by username? Is it an attribute of a collection you've created?

No the Authentication side of appwrite

That's just the name field and not username. I don't think you can prevent the names from being changed in auth. You can, however, create a collection for usernames and set the appropriate permissions and create a function to create the usernames. So essentially, you'll not use the name attribute in auth at all.