561 Group Market

SEN Coincide

Judge whether two Mark payloads coincide as token carriers: a witness or an obstruction.

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/sen/coincide
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": {
      "left": {},
      "right": {}
    },
    "required": [
      "left",
      "right"
    ]
  }
}

Example request

{
  "method": "POST",
  "url": "https://market.561.group/v1/sen/coincide",
  "headers": {
    "accept": "application/json",
    "content-type": "application/json"
  },
  "body": {
    "left": "alice",
    "right": "alice"
  }
}

Output

{
  "schema": {
    "type": "object",
    "properties": {
      "kind": {
        "type": "string"
      },
      "left": {},
      "right": {}
    }
  },
  "example": {
    "kind": "signcell.coincidence:witness",
    "left": "alice",
    "right": "alice"
  }
}

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 '{"left":"alice","right":"alice"}' --url 'https://market.561.group/v1/sen/coincide'

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

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