Advanced Validation

Use these rules when a normal required/type check is not enough for the data you collect.

Rules

Rule	Use it for
regex	Admin-supplied PCRE patterns
custom	Restricting values to a chosen character set
creditcard	Luhn + common brand-prefix checks
iban	ISO 13616 country-length and checksum validation
restrictedwords	Blocking chosen words server-side
multiplerules	Combining several rules with all or any logic
emaildns	Email syntax plus live MX probing
password	Passphrase-gated submission with bcrypt storage

Add a rule

1. Open a field in the builder.
2. Enable Advanced validation.
3. Add the rule you need.
4. Configure its parameters and custom error message.

The same rule set runs in the browser and on the server where appropriate. The password rule stays server-side and visitor attempts are redacted before storage.