Which Characters Can be Used in 'Member Management' Email Addresses and Validation Rules?

Which characters can be used in 'Member Management' email addresses?

By default, Kuroco validates email addresses using a specific regular expression pattern. However, you can configure it to use RFC-compliant email address validation instead.

Email Validation Regex

Kuroco uses the following regular expression pattern for email address validation with the preg_match() function:

preg_match('/^[a-zA-Z0-9.+!#$&*=?^_{|}~-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/', $email_address)

This regular expression validates email addresses with the following criteria:

• Local part (before @): Alphanumeric characters, period, percent, plus, exclamation mark, hash, ampersand, asterisk, equals, question mark, caret, underscore, pipe, tilde, and hyphen are allowed
• Domain part (after @): Alphanumeric characters, period, and hyphen are allowed, with a top-level domain of at least 2 characters required

Email Validation Function Implementation

Kuroco uses the is_email() function for email validation, which has two different validation modes depending on configuration:

Validation Modes

Default Behavior (Regular Expression Validation):
By default, Kuroco uses custom regex pattern validation with the following characteristics:

• Enforces a maximum length of 256 characters
• Allow a specifically defined character set.
• This is the standard validation method used when no special configuration is set

RFC Compliance Mode (Activated by STRICT_VALIDATE_EMAIL Constant):
When you set the STRICT_VALIDATE_EMAIL constant, the validation switches to full RFC compliance:

• Provides complete RFC compliance according to official email address standards
• No custom length restrictions beyond RFC specifications
• More permissive than the default regex validation

To switch from default regex validation to RFC compliance, define:

STRICT_VALIDATE_EMAIL = 1;

This constant changes the validation behavior from custom regex pattern matching to standard RFC-compliant email validation.

info

You can configure constants like STRICT_VALIDATE_EMAIL through the Constants Management screen in your Kuroco admin panel.