561 Group Market

UTF-8 Form Data to Ordered JSON Pairs

Decode application/x-www-form-urlencoded text into ordered string pairs. Preserve duplicate/empty keys, blank values and Unicode. Loss-refusing UTF-8 profile: reject malformed escapes and UTF-8 before payment. Up to 65536 input/output bytes and 2048 pairs; no upstream compute.

Price
from $0.0012 USDC per request (starting price; the 402 response quotes the exact amount for your input)
Network
Base mainnet, eip155:8453, settled in USDC through the Coinbase CDP facilitator
Method and URL
POST https://market.561.group/v1/data/form-to-json
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": false,
    "required": [
      "text"
    ],
    "properties": {
      "text": {
        "type": "string",
        "maxLength": 65536
      }
    }
  }
}

Example request

{
  "method": "POST",
  "url": "https://market.561.group/v1/data/form-to-json",
  "headers": {
    "accept": "application/json",
    "content-type": "application/json"
  },
  "body": {
    "text": "x=1&x=2&name=Phez%CC%8Ci+Ocha%CC%81%C7%A7e&blank="
  }
}

Output

{
  "schema": {
    "type": "object",
    "additionalProperties": false,
    "required": [
      "pairs"
    ],
    "properties": {
      "pairs": {
        "type": "array"
      }
    }
  },
  "example": {
    "pairs": [
      [
        "x",
        "1"
      ],
      [
        "x",
        "2"
      ],
      [
        "name",
        "Pheži Ocháǧe"
      ],
      [
        "blank",
        ""
      ]
    ]
  }
}

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 '{"text":"x=1&x=2&name=Phez%CC%8Ci+Ocha%CC%81%C7%A7e&blank="}' --url 'https://market.561.group/v1/data/form-to-json'

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

Machine-readable