The global foundation of the payment-card tool is Luhn validation plus card-network range recognition. The input is processed in the browser. Once it reaches a common card-number length, the page shows the Luhn result, likely network and any issuer hint available from the built-in BIN/IIN table.

BIN data changes and requires an authoritative, continuously maintained source, so issuer enrichment is optional and incomplete. It is never required for deciding whether the number is structurally valid.

1. 01Enter or paste a 12–19 digit card number; spaces can remain in the displayed value.
2. 02The tool applies the Luhn mod-10 check digit algorithm.
3. 03It examines number prefixes for common card networks.
4. 04If the local BIN table has a match, it also shows a possible issuer and card type.

Luhn catches many common transcription errors, but anyone can construct a test number that passes Luhn, so it is not an online card verification system. Network recognition relies on public IIN ranges. Specific bank BIN data is finer-grained and changes more frequently, so it must remain separate from the checksum result.

• A passing Luhn check does not prove the card exists, can transact, is not blocked or has funds.
• The built-in issuer BIN table is not a complete global database. A miss cannot determine the issuing bank or country.
• The tool does not query cardholder names, balances, transactions, CVVs, expiry dates or live bank status.
• Never enter CVV, PIN, SMS codes or other authentication secrets.

• Test Luhn validation in a payment form.
• Catch obvious manual-entry errors.
• Distinguish common Visa/Mastercard/Amex/JCB/Discover/UnionPay ranges.
• Add reliable BIN enrichment later without changing the Luhn core.

Card numbers are parsed locally in the browser and are not uploaded to Toolun. Complete payment-card numbers are still sensitive financial data. Prefer official test numbers for development and never enter CVV, PIN or one-time authentication codes.