SPARQL over public merchant service metadata

Query the fixed source-versioned public merchant metadata graph. English, Spanish and Arabic labels share stable service IRIs. Shared labels retain distinct subjects. Returns the existing RDF JSON result carrier; the caller cannot replace the seller-selected dataset.

Seller-listed; delivery not independently established — A listing is not a completed purchase. The live HTTP 402 challenge supplies current payment terms.

Price preview: $0.01
Method: POST
Endpoint: https://market.561.group/v1/knowledge/service-graph
Seller: Seller not independently established
Source-rights state: not-declared
Offer NI: ni:///sha-256;UP7Xb-aTjnWV5Pkd86LQUADmNX9Pajd38I-TJMCcarc
Claim cell: ni:///sha-256;LmFh4vxA2LIAUqtOzGQxBS-1XceTjG2RHiip78fIzDM
Operation law: ni:///sha-256;Z1xlrlUkFIlRC8PJQMmkJiD7zVH8cWG9T9j-2uM-Iyw

knowledge-query
query-public-service-graph
data
ni:///sha-256;UP7Xb-aTjnWV5Pkd86LQUADmNX9Pajd38I-TJMCcarc
@red-cup-engineering/computer-triplet-serialized-content-engineering-services-section

The seller offers this resource under the stated method and contract. The price is a preview, not payment authorization, settlement or a promise of delivery.

Request contract

{
  "maxBytes": 131072,
  "bodySchema": {
    "type": "object",
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "required": [
      "query"
    ],
    "additionalProperties": false,
    "properties": {
      "query": {
        "type": "string",
        "minLength": 1,
        "maxLength": 8192
      }
    }
  },
  "example": {
    "method": "POST",
    "url": "https://market.561.group/v1/knowledge/service-graph",
    "headers": {
      "accept": "application/json",
      "content-type": "application/json"
    },
    "body": {
      "query": "SELECT ?label WHERE { <https://market.561.group/v1/knowledge/sparql> <https://schema.org/name> ?label } LIMIT 8"
    }
  }
}

Unsigned request example (copy and run)

curl --include --request POST --header 'accept: application/json' --header 'content-type: application/json' --data-raw '{"query":"SELECT ?label WHERE { <https://market.561.group/v1/knowledge/sparql> <https://schema.org/name> ?label } LIMIT 8"}' --url 'https://market.561.group/v1/knowledge/service-graph'

This request reads the seller's current HTTP response or 402 terms. It does not authorize or settle a payment. A buyer must independently approve current x402 terms.

Declared output

{
  "schema": {
    "type": "object",
    "required": [
      "type",
      "mediaType",
      "body"
    ],
    "additionalProperties": false,
    "properties": {
      "type": {
        "enum": [
          "select",
          "ask",
          "construct"
        ]
      },
      "mediaType": {
        "enum": [
          "application/sparql-results+json",
          "text/turtle"
        ]
      },
      "body": {
        "type": "string"
      }
    }
  },
  "example": {
    "type": "select",
    "mediaType": "application/sparql-results+json",
    "body": "{\"head\":{\"vars\":[\"label\"]},\"results\":{\"bindings\":[{\"label\":{\"type\":\"literal\",\"value\":\"استعلام RDF متعدد اللغات\",\"xml:lang\":\"ar\"}},{\"label\":{\"type\":\"literal\",\"value\":\"Multilingual RDF query\",\"xml:lang\":\"en\"}},{\"label\":{\"type\":\"literal\",\"value\":\"Consulta RDF multilingüe\",\"xml:lang\":\"es\"}}]}}\n"
  }
}

View unsigned request example

Preview one-call atomic budget

How to buy with x402

Send the source's unsigned request. An admitted payable request receives HTTP 402 and a PAYMENT-REQUIRED header with its current amount, asset, network and payee.
Your x402 client signs the accepted terms and repeats the same request with PAYMENT-SIGNATURE.
A successful settled response contains the purchased result and its PAYMENT-RESPONSE receipt.

How x402 purchasing works

Source and machine access

The source SKU, claim cell and operation law above are the identities used by the machine catalogue and this page.