How to do extra username validation on new user registraiton

Hi,
You can use the ‘wppb_check_form_field_default-username’ filter to achieve that.

Here’s a code sample to add some extra validation to the username field:

//Extra validation for username field
function wppb_extra_username_validation( $message, $field, $request_data, $form_location){
    if ('add your extra validation here'){
            return __( 'Add your error message here.', 'profilebuilder' );
        }
    return $message;
}
add_filter('wppb_check_form_field_default-username','wppb_extra_username_validation', 10, 4);

Make sure to add your own validation conditions and desired error message.

Thank you so much, it works. Cheers!

No worries, glad it works! If you find Profile Builder useful, please consider leaving a review.