561 Group Market

Content Address

The exact, deterministic content id of one JSON value under one named object kind (SHA-256 over its canonical SEN encoding): the same value and kind always produce the same address.

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/content-address
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": {
      "objectKind": {
        "type": "string"
      },
      "value": {}
    },
    "required": [
      "objectKind",
      "value"
    ]
  }
}

Example request

{
  "method": "POST",
  "url": "https://market.561.group/v1/content-address",
  "headers": {
    "accept": "application/json",
    "content-type": "application/json"
  },
  "body": {
    "objectKind": "example.document",
    "value": {
      "title": "Hello",
      "tags": [
        "a",
        "b"
      ]
    }
  }
}

Output

{
  "schema": {
    "type": "object",
    "properties": {
      "id": {
        "type": "string"
      },
      "token": {
        "type": "string"
      },
      "algorithm": {
        "type": "string"
      },
      "mediaType": {
        "type": "string"
      }
    }
  },
  "example": {
    "id": "ni:///sha-256;mXRmsG8UWz_BSqa0RxpH9aA_fL6_O1LvXZFPMJoQrnw",
    "token": "ni:///sha-256;mXRmsG8UWz_BSqa0RxpH9aA_fL6_O1LvXZFPMJoQrnw",
    "algorithm": "sha-256",
    "mediaType": "application/sen+cbor"
  }
}

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 '{"objectKind":"example.document","value":{"title":"Hello","tags":["a","b"]}}' --url 'https://market.561.group/v1/content-address'

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

Machine-readable