Creating unique custom attributes on AWS Cognito

Question

I need to create a custom attribute that is unique for each of the users inside my User Pool. Is there a way for me to do it with a custom attribute using AWS Cognito?

I'm integrating the AWS-SDK in JavaScript.

Answer 1

Such a setting is not possible for custom attributes. The only attributes that work that way are alias attributes (they will need to be unique). These are email, phone_number, and preferred_username. Email and phone_number would need to be verified to be used that way. The only workaround I can think about is using one of the aliases to emulate this behavior.