Card number validate

Validate a payment card number (Luhn checksum) and detect the brand. Numbers are not stored or logged.

Input

Field	Type	Description
number *	string	Card number (spaces/dashes allowed)

Example output

{
  "valid": true,
  "brand": "visa",
  "length": 16
}

Try it — see the 402 challenge (free)

curl -i -X POST https://agent402.tools/api/card-validate \
  -H "Content-Type: application/json" \
  -d '{"number":"4242 4242 4242 4242"}'

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/card-validate", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "number": "4242 4242 4242 4242"
  }),
});

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