x402 endpoint preflight / landmine detector API

Do one unpaid probe of an x402 endpoint and classify it before you spend a payment — verify it returns a well-formed HTTP 402 with parseable payment requirements and extract the advertised price/network/asset, or flag it dead, not-x402, or malformed. The value-add is a maintained probe + classification so agents don't waste a payment on a honeypot, dead host, or misconfigured server. Answers 'is this x402 endpoint real before I pay', 'what price/network/asset does this endpoint advertise', 'is this endpoint a honeypot or dead'.

Price$0.03per request

MethodPOST

Route/v1/x402/preflight

StatusLive

MIME typeapplication/json

Rate limit60/minute

Cache300s public

x402preflightlandmineendpointvalidatehoneypot402payment-requirements

API URLhttps://x402.hexl.dev/v1/x402/preflight

Integration docs

Example request

{
  "url": "https://api.example.com/v1/search"
}

Example response

{
  "url": "https://api.example.com/v1/search",
  "reachable": true,
  "returns402": true,
  "advertised": {
    "price": "10000",
    "network": "base",
    "asset": "USDC"
  },
  "verdict": "ok",
  "signals": [
    "returned HTTP 402 Payment Required",
    "advertised price 10000",
    "network base",
    "asset USDC"
  ],
  "probedAt": "2026-06-03T00:00:00.000Z"
}

Input schema

{
  "type": "object",
  "required": [
    "url"
  ],
  "properties": {
    "url": {
      "type": "string",
      "format": "uri",
      "examples": [
        "https://api.example.com/v1/search"
      ]
    }
  },
  "examples": [
    {
      "url": "https://api.example.com/v1/search"
    }
  ]
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}