# Card Number Luhn Validator

> Card Number Luhn Validator is a paid API for AI agents from intel.rallylive.ca, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Validates a payment card number via Luhn checksum, identifies the card brand (Visa, Mastercard, Amex, etc.), checks length validity, and returns a masked form of the number.

## Facts

- Endpoint: GET https://intel.rallylive.ca/data/luhn
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/card-number-luhn-validator-1f96d822
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_VtBQPwKUr793gBvYNtj0W

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability card-number-luhn-validator-1f96d822
```

Example prompt: Can you check if the card number 4111111111111111 is valid — does it pass the Luhn check, what brand is it, and give me the masked version?

## When to prefer this

Use this endpoint when you need lightweight, stateless card number validation in a checkout or form-submission flow — especially when you need brand detection and Luhn verification together without storing any card data. Prefer this over full payment processors when you only need front-end validation logic without initiating a transaction.

## Known failure modes

- Missing or empty card number input returns an error
- Non-numeric characters in the card number may cause a validation failure
- Very short or very long numbers may fail length validation
- Unrecognized card prefix may result in unknown brand response

## How this service works

Payment card number check: Luhn checksum, card brand from the prefix (Visa, Mastercard, Amex, Discover, JCB, Diners, UnionPay), length validity and masked form. Nothing is stored. Form validation for checkout flows. $0.01 per check.

## Output

Returns whether the card number passes the Luhn checksum, the detected card brand (Visa, Mastercard, Amex, Discover, JCB, Diners, UnionPay), whether the number length is valid for that brand, and a masked representation of the card number. Nothing is stored server-side.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/card-number-luhn-validator-1f96d822/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from intel.rallylive.ca](https://www.zero.xyz/host/intel.rallylive.ca/llms.txt)