Block Specific Characters in a User's Email Address During Registration

This article clarifies whether it is possible to block specific characters from an email address during user creation. A user's email address contains invalid characters, such as ?, /, or #, preventing its use during registration.

• User registration
• Pre-User-Registration Trigger
• Actions

A direct way to block specific characters from an email address is not available in the Auth0 dashboard user interface (UI). This functionality is achievable using a Pre-User-Registration Trigger in Actions.

Use the following sample code for the Action:

/**

 * @param {Event} event - Details about the user and the context of the registration.

 * @param {PreUserRegistrationAPI} api - Interface to modify the context of the registration.

 */

exports.onExecutePreUserRegistration = async (event, api) => {

 const email = event.user.email;

 if (!email) {

  return;

 }

 const forbiddenCharsRegex = /[?;/"\[\]#]/;

 const hasForbiddenChars = forbiddenCharsRegex.test(email);

 if (hasForbiddenChars) {

  api.validation.error(

   "invalid_email_format",

   "Your email address contains invalid characters and cannot be used."

  );

 }

};

This code snippet blocks characters such as ?, ;, /, ", [, ], and #.