Edge is just where something is hosted. It has nothing to do with data consistency. User signup is a unique problem that any large site has. Some sites like HN

Edge is just where something is hosted. It has nothing to do with data consistency. User signup is a unique problem that any large site has. Some sites like HN also actually needs usernames which makes things more complicated. Owasp always recommend to add usernames to any login. It is such a naive approach. User names are garbage in most cases.