Luhn check API: validate card and IMEI numbers, compute check digit
Luhn check: whether a card number or other ID passes the Luhn (mod 10) algorithm used by card numbers, IMEI numbers and many IDs, and compute the check digit to append. Only the format is checked; nothing is looked up. Use to catch typos in card or ID numbers.
When to use it
- Catch typos in card or ID numbers
- Compute the check digit to append to a number
$0.001 per call with prepaid credits: $1 by card pays for 1,000 calls, with no account and no subscription.
Inputs
| Name | Type | Description |
|---|---|---|
number (required) | string | Digits, spaces and hyphens allowed |
Request
Over HTTP, with a card key from /credits:
curl -H "Authorization: Bearer adt_…" "https://glyphcall.com/validate/luhn?number=79927398713"Or one of your 3 free calls, no key:
curl "https://glyphcall.com/validate/luhn?number=79927398713&trial=1"Without a key, the same URL answers 402 Payment Required with x402 and MPP terms, so an agent with a wallet pays per call in USDC (Base, Polygon, Arbitrum or Solana over x402; Base or Tempo over MPP) and retries.
Example result
{
"digits": "79927398713",
"valid": true,
"checkDigitForPrefix": 3
}From an AI agent (MCP)
Add the MCP server to Claude, Cursor or any MCP client. This tool is validate_luhn, and the first 25 successful calls are free:
https://glyphcall.com/mcpQuestions
Does it check whether the card exists?
No. Only the format (mod 10) is checked; nothing is looked up.
How do I pay?
Each successful call costs $0.01; failed calls are not charged. The first 3 calls are free (25 through an MCP client). Then pay with card credits (from $1; the key goes in an Authorization header or, for clients that can only fetch a URL, as api_key= in the URL) or per call in USDC over x402 or MPP. No account is needed.