561 Group Market

Reference Check

Check up to 25 citation strings or CSL-JSON items against CrossRef and OpenAlex for DOI/scholarly records and Open Library for ISBN/book records. Each result returns the parsed or supplied item, identifier/search used, matched record, evidence URLs, and the house FOUR truth reading: true=supported, false=identifier resolves to another work, both=sources disagree, neither=nothing found. A match requires a closely matching folded title and exact folded first-author family name.

Price
$0.02 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/reference-check
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": {
      "references": {
        "type": "array",
        "maxItems": 25,
        "items": {
          "oneOf": [
            {
              "type": "string"
            },
            {
              "type": "object"
            }
          ]
        }
      }
    },
    "required": [
      "references"
    ]
  }
}

Example request

{
  "method": "POST",
  "url": "https://market.561.group/v1/reference-check",
  "headers": {
    "accept": "application/json",
    "content-type": "application/json"
  },
  "body": {
    "references": [
      "Sénéchal, M., & Young, L. (2008). The effect of family literacy interventions on children's acquisition of reading. Review of Educational Research, 78(4), 880–907. doi:10.3102/0034654308320319",
      "Davis, E. (2019). The Library as Liberation. Journal of Imaginary Studies 12(3).",
      {
        "type": "book",
        "title": "The Snowy Day",
        "author": [
          {
            "family": "Keats",
            "given": "Ezra Jack"
          }
        ],
        "ISBN": "9780670654000"
      }
    ]
  }
}

Output

{
  "schema": {
    "type": "object",
    "required": [
      "results"
    ],
    "properties": {
      "results": {
        "type": "array",
        "maxItems": 25,
        "items": {
          "type": "object",
          "required": [
            "input",
            "item",
            "identifier",
            "matched",
            "read",
            "evidence"
          ],
          "properties": {
            "item": {
              "type": [
                "object",
                "null"
              ]
            },
            "identifier": {
              "type": [
                "object",
                "null"
              ]
            },
            "matched": {
              "type": [
                "object",
                "null"
              ]
            },
            "read": {
              "enum": [
                "neither",
                "true",
                "false",
                "both"
              ]
            },
            "evidence": {
              "type": "array",
              "items": {
                "type": "string"
              }
            }
          }
        }
      }
    }
  },
  "example": {
    "results": [
      {
        "input": {
          "type": "book",
          "title": "The Snowy Day",
          "author": [
            {
              "family": "Keats",
              "given": "Ezra Jack"
            }
          ],
          "ISBN": "9780670654000"
        },
        "item": {
          "type": "book",
          "title": "The Snowy Day",
          "author": [
            {
              "family": "Keats",
              "given": "Ezra Jack"
            }
          ],
          "ISBN": "9780670654000"
        },
        "identifier": {
          "type": "ISBN",
          "value": "9780670654000",
          "via": "Open Library"
        },
        "matched": {
          "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"
        },
        "read": "true",
        "evidence": [
          "https://openlibrary.org/isbn/9780670654000.json",
          "https://openlibrary.org/works/OL45804W.json",
          "https://openlibrary.org/authors/OL22242A.json"
        ]
      }
    ]
  }
}

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 '{"references":["Sénéchal, M., & Young, L. (2008). The effect of family literacy interventions on children'\''s acquisition of reading. Review of Educational Research, 78(4), 880–907. doi:10.3102/0034654308320319","Davis, E. (2019). The Library as Liberation. Journal of Imaginary Studies 12(3).",{"type":"book","title":"The Snowy Day","author":[{"family":"Keats","given":"Ezra Jack"}],"ISBN":"9780670654000"}]}' --url 'https://market.561.group/v1/reference-check'

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

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