561 Group Market

FOUR Evidence Point Census

Count up to 14627 named FOUR points by knowledge-family names absurd, potential, active, stable. Mixed naming families are accepted because this counts their common underlying points. Empty input returns zero counts. Names are not verified observations or independent witnesses.

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/four/reading-census
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",
    "additionalProperties": true,
    "required": [
      "names"
    ],
    "properties": {
      "names": {
        "type": "array",
        "maxItems": 14627,
        "items": {
          "type": "string",
          "enum": [
            "absurd",
            "potential",
            "active",
            "stable",
            "told none",
            "told true",
            "told false",
            "told both",
            "neither",
            "true",
            "false",
            "both",
            "unknown",
            "held",
            "denied",
            "contested"
          ]
        }
      }
    }
  }
}

Example request

{
  "method": "POST",
  "url": "https://market.561.group/v1/four/reading-census",
  "headers": {
    "accept": "application/json",
    "content-type": "application/json"
  },
  "body": {
    "names": [
      "held",
      "held",
      "denied",
      "unknown"
    ]
  }
}

Output

{
  "schema": {
    "type": "object",
    "properties": {
      "absurd": {
        "type": "integer"
      },
      "potential": {
        "type": "integer"
      },
      "active": {
        "type": "integer"
      },
      "stable": {
        "type": "integer"
      }
    }
  },
  "example": {
    "absurd": 1,
    "potential": 2,
    "active": 1,
    "stable": 0
  }
}

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 '{"names":["held","held","denied","unknown"]}' --url 'https://market.561.group/v1/four/reading-census'

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

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