Is it possible to prevent duplicate emails from signing up?

[dan.woda]

Hi @nakatatsu711,

Welcome to the Auth0 Community!

I understand you’d like to prevent signups from users that have already created an account with the same email in a different connection/provider.

It doesn’t seem possible using a hook/pre registration action due to the fact that these don’t run for any connections that are database connection (they don’t run for social connections for example).

There are some strategies outlined in this thread:

Prevent multiple signups with the same email across different connections

Hi @hesperanca A possible technique I would suggest (as we do this in our organization) is to not merge identities in Auth0 and keep them separate and handle the merging in your system. The advantage of this is by default the identity will be treated as a separate user so there will be no accidental merging of accounts. The disadvantage is that instead of linking Auth0 to your system using email, you must link Auth0 using the Auth0 ID number provided. This method will give you more control o…

It might be worth it to create a Feature Request for this as it seems like there is some demand.