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checkdigit.openverbs.com v1 luhn
https://checkdigit.openverbs.com/v1/luhn
answers 402
Validate a number by the Luhn (mod-10) algorithm — the scheme behind credit/debit card numbers and many IDs. Spaces and hyphens are ignored. A mismatched check digit is a successful { valid: false }.
We sent a real
POST request to this endpoint and it
answered 402 with payment requirements we could parse.
- Price
- $0.002
- Network
- base
- Pay to
- 0xb3f4de103F34b99f0Da19B4F16D6B53a14C2194A
- Spec dialect
- v2 (declares x402Version 2)
- Transport
- PAYMENT-REQUIRED header
- HTTP method
- POST
- Response latency
- 241 ms
- Payment options
- 1 usable of 1
- Last checked
- 2026-09-06T01:20:14.489Z (21d ago)
- Category
- other
Re-check it yourself:
curl "https://api.the402.dev/validate?url=https%3A%2F%2Fcheckdigit.openverbs.com%2Fv1%2Fluhn"