561 Group Market

Book Record

Validate one ISBN checksum and return its Open Library edition, work and author records projected into one sourced CSL-JSON book item; invalid or absent ISBNs return an explicit refusal. The FOUR truth reading is true when found and neither on refusal.

Price
$0.002 USDC per request
Network
Base mainnet, eip155:8453, settled in USDC through the Coinbase CDP facilitator
Method and URL
POST https://market.561.group/v1/book-record
Response type
application/json
Seller
Causeway Services (561 Group)

Input contract

Input that fails this contract is refused with a 4xx status before any payment is requested.

{
  "maxBytes": 102400,
  "bodySchema": {
    "type": "object",
    "properties": {
      "isbn": {
        "type": "string",
        "description": "An ISBN-10 or ISBN-13, with or without hyphens."
      }
    },
    "required": [
      "isbn"
    ]
  }
}

Example request

{
  "method": "POST",
  "url": "https://market.561.group/v1/book-record",
  "headers": {
    "accept": "application/json",
    "content-type": "application/json"
  },
  "body": {
    "isbn": "9780670654000"
  }
}

Output

{
  "schema": {
    "type": "object",
    "required": [
      "sources",
      "read"
    ],
    "properties": {
      "record": {
        "type": "object",
        "description": "The normalized CSL-JSON book record when found."
      },
      "refusal": {
        "type": "object",
        "description": "The invalid-checksum or not-found refusal when no record can be returned."
      },
      "sources": {
        "type": "array",
        "items": {
          "type": "string"
        }
      },
      "read": {
        "enum": [
          "neither",
          "true",
          "false",
          "both"
        ]
      }
    }
  },
  "example": {
    "record": {
      "id": "9780670654000",
      "type": "book",
      "title": "The Snowy Day",
      "author": [
        {
          "family": "Keats",
          "given": "Ezra Jack"
        }
      ],
      "issued": {
        "date-parts": [
          [
            1962
          ]
        ]
      },
      "publisher": "Viking Press",
      "ISBN": "9780670654000",
      "number-of-pages": 32,
      "URL": "https://openlibrary.org/isbn/9780670654000",
      "note": "Open Library sources: https://openlibrary.org/isbn/9780670654000.json, https://openlibrary.org/works/OL45804W.json, https://openlibrary.org/authors/OL22242A.json"
    },
    "sources": [
      "https://openlibrary.org/isbn/9780670654000.json",
      "https://openlibrary.org/works/OL45804W.json",
      "https://openlibrary.org/authors/OL22242A.json"
    ],
    "read": "true"
  }
}

How to buy with x402

  1. Send the request without payment. The server answers 402 Payment Required with a base64 JSON PAYMENT-REQUIRED header holding the amount, asset, network and payee.
  2. Have your wallet sign an EIP-3009 transferWithAuthorization for exactly those terms (an x402 client library does this for you).
  3. Repeat the identical request with the signed payload in the PAYMENT-SIGNATURE header.
  4. The server verifies, runs the operation, settles, and returns 200 with the result and a PAYMENT-RESPONSE header carrying the settlement receipt.

Read the price without paying

curl --include --request POST --header 'accept: application/json' --header 'content-type: application/json' --data-raw '{"isbn":"9780670654000"}' --url 'https://market.561.group/v1/book-record'

This request authorizes nothing; it returns the live payment terms. Read the full explanation of x402.

Machine-readable