Validate an ISBN

$0.003 per call · failed calls are never charged · no account or API key needed

Check an ISBN-10 or ISBN-13 check digit and convert valid ISBN-10s to ISBN-13. Hyphens and spaces are ignored. Use before cataloguing or ordering books.

Run it free (25 free calls) Buy credits by card (from $5) Example result (JSON)

Inputs

NameTypeDescription
isbn (required)stringThe ISBN

Request

Over HTTP, with a card key from /credits:

curl -H "Authorization: Bearer adt_…" "https://agent-data-tools.revmesh2074.workers.dev/validate/isbn?isbn=0-306-40615-2"

Or one of your 25 free calls, no key:

curl "https://agent-data-tools.revmesh2074.workers.dev/validate/isbn?isbn=0-306-40615-2&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, Monad, World Chain or Tempo) and retries.

Example result

{
  "isbn": "0306406152",
  "type": "ISBN-10",
  "valid": true,
  "isbn13": "9780306406157"
}

From an AI agent (MCP)

Add the MCP server to Claude, Cursor or any MCP client. This tool is validate_isbn, and the first 25 successful calls are free:

https://agent-data-tools.revmesh2074.workers.dev/mcp

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