Luhn-validate a card number and detect its network brand (Visa/Mastercard/Amex/Discover/Diners/JCB/UnionPay) from IIN prefix + length. Formula only, not a real-card check.
Free tier eligible — 500 calls/month with a free key from /pricing; x402 pay-per-call above quota.
Edit the JSON and run it — this POSTs to https://wingmanprotocol.com/tools/card_brand_detect from your browser.
This tool is x402-metered — agents pay per call with USDC on Base. The 402 response below is the standard x402 payment-requirements envelope: sign the EIP-3009 authorization and retry with the X-Payment header, or get a free key at /pricing (500 calls/month, no card, no crypto).