Restrict the Use of Special Characters in Sign Up Emails

Last Updated: Sep 10, 2025

Overview

The end-users can use non-alphanumerical/special characters in email addresses.

For example: 山田@日本.com

Although it is a valid internationalized email address, some applications cannot handle such an email.

This article details how to disallow the use of non-alphanumerical characters on sign-up.

Applies To

Email
Special Characters
Sign Up

Solution

An email address can be validated in Pre-User Registration Actions.

Check the email matches are composed of only alphanumeric characters.
Use "api.access.deny" when the email does not pass the validation.

NOTE: This approach only works for regular database connections. Pre-User Registration Actions will not run when users are logging in with Social / Enterprise SSO or when importing users from the eternal database.