Unconfirmed email in cognito userpool

Question

I'm filtering email in pre-signup lambda function those emails are in cognito userpool can't be used again for sign up, but there is a situation if user leaves an email unconfirmed and latter user uses that mail for signup then pre-signup function will not allow. Tell me should I filter email in lambda or remove the lambda and allow duplicate entries?![Enter image description here](https://repost.aws/media/postImages/original/IMrVjzDIuxQImDzLVVQpbG-w)

Maverick · Accepted Answer

I would suggest you 2 approaches:

* I would suggest to enforce “Allow Cognito to automatically send messages to verify and confirm - Recommended”**, this will avoid having spoof email users duplicated, as the email will require confirmation for account creation, mitigating duplicates with unverified emails. 
![Cognito UserPooll Configuration](/media/postImages/original/IM9EPEfB6HRJyNbBVz3Fprrg)
* The second option is to have a scheduled Lambda to check and verify emails against unverified and clean up accounts that are not necessary; this is not a best practice as you may run into issues Lambda Timing out after 15 min (depending of the size/users inside of the UserPool), you may want to use this to clean the UserPool, but I would suggest you to look into a different Sign-up flow.

Unconfirmed email in cognito userpool

Relevant content