Regex Editor & Tester

Matches Visa credit or debit card numbers, which must start with the digit 4 and be either 13 or 16 digits long (the optional non-capturing group adds the final three digits for standard 16-digit cards). Anchors (^ and $) ensure the whole string conforms to Visa's numbering format. Useful for basic card type detection and payment form validation, though it does not verify the Luhn checksum.