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fastapi.online Luhn Algorithm Validator
x402
fastapi.online Luhn Algorithm Validator is a paid API for AI agents from api.fastapi.online, paid per call via x402, $0.0005/call, status unknown (last checked 2026-09-15).
Validates a numeric string using the Luhn algorithm, typically used to verify credit card, IMEI, or other check-digit numbers
Price / call$0.0005
Success—
StatusUnknown
How this service works
Chat, embeddings, OCR, speech-to-text, image editing, image understanding (captioning/Q&A), text-to-speech, translation, writing tools, classification tools, developer tools, local utilities, format/checksum validators, encoding & crypto utilities, date/time calculators, geo/coordinate math, math & finance calculators, novelty tools, and business/social writing generators — 179 endpoints in all, across multiple specialized self-hosted models. Pay per call with crypto — no signup — or get an API key.
Output
Returns a validation result indicating whether the submitted numeric string passes the Luhn algorithm check — typically a boolean or pass/fail status indicating whether the check digit is correct.
Example use cases
Pre-payment card number check
“Before I submit this transaction, can you verify that the card number 4111111111111111 passes the Luhn algorithm so I know it's not obviously invalid?”
IMEI number authenticity check
“I have an IMEI number 490154203237518 — can you run it through the Luhn validator to see if it's a legitimate format?”
Bulk order form input sanity check
“A user just entered 1234567890123456 as their card number in our checkout form — can you Luhn-validate it before we even attempt to charge them?”
Technical details
Endpoint
POSThttps://api.fastapi.online/luhn-validateWhen to prefer
Choose this endpoint when you need a quick, cheap ($0.0005 USDC), no-signup Luhn checksum validation callable via a simple POST with no authentication setup. Ideal for agents or pipelines that need on-demand card/IMEI number pre-validation without integrating a full payment processing SDK or standing up local checksum logic.
Side effects
- Input contains non-numeric characters — rejected or fails validation
- String too short or too long (outside 1–40 character bounds)
- Empty string submitted — validation error returned
- Network or payment gateway error if crypto micropayment fails
- Ambiguous response if the API returns an error instead of a clean boolean
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| number | string |
Tags
x402
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