api402x.com

Live 402 challenge

Captured by the enrichment pass, not read just now. Prices can change — always read the 402 the endpoint answers with.

{
  "what": "Does a catalogue listing still match what the origin serves? Calls the resource with no payment, reads the price, network and payTo out of the 402 the origin itself returns, and compares them with the price the catalogue advertises. The 402 is the authoritative statement; the catalogue is a cache of one. Also separates two failures no catalogue reports: an origin that is gone, and an origin that answers but whose response headers exceed the 16384-byte ceiling Node applies to all response headers combined -- live, indexed and impossible to pay from a Node client. Required: resource. Optional: advertised_price. Honest note: demand for this route is not measured; it exists because the defect it reports was measured on our own surface first.",
  "asset": "USDC",
  "error": "payment_required",
  "price": "$0.002",
  "accepts": [
    {
      "payTo": "0x63bc58472a8449eDd1d1af0B0c03cFc7c832Da2f",
      "price": "$0.002",
      "scheme": "exact",
      "network": "eip155:8453"
    },
    {
      "payTo": "0x63bc58472a8449eDd1d1af0B0c03cFc7c832Da2f",
      "price": {
        "asset": "0xfde4C96c8593536E31F229ea8F37b2Ada2699bb2",
        "extra": {
          "assetTransferMethod": "permit2"
        },
        "amount": "2000"
      },
      "scheme": "exact",
      "network": "eip155:8453"
    },
    {
      "payTo": "0x63bc58472a8449eDd1d1af0B0c03cFc7c832Da2f",
      "price": {
        "asset": "0x50c5725949A6F0c72E6C4a641F24049A917DB0Cb",
        "extra": {
          "supportsEip2612": true,
          "assetTransferMethod": "permit2"
        },
        "amount": "2000000000000000"
      },
      "scheme": "exact",
      "network": "eip155:8453"
    }
  ],
  "example": "https://api402x.com/x402-listing-drift-check?resource=https%3A%2F%2Fapi.example.com%2Fsome-paid-route&advertised_price=%240.005",
  "network": "eip155:8453",
  "openapi": "https://api402x.com/openapi.json",
  "how_to_pay": "x402: signed payment challenge is in the `payment-required` response header. No API key and no subscription — pay per call in USDC on Base.",
  "x402Version": 2,
  "free_preview": "https://api402x.com/x402-listing-drift-check/preview",
  "authoritative": "payment-required header; this body is a duplicate for clients that read the body"
}

Accepts

The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.

[
  {
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "extra": {
      "name": "USD Coin",
      "version": "2"
    },
    "payTo": "0xE606AE66542D4F1A56AA551841db41e3ECd26816",
    "amount": "2000",
    "scheme": "exact",
    "network": "eip155:8453",
    "maxTimeoutSeconds": 300
  }
]

Provenance

Seen in the source catalog

2026-08-28 04:31Z

Last indexed by Roundhouse

2026-09-21 13:45Z

Last enriched (probe, favicon, geo)

2026-09-18 17:15Z

x402 version

2

Max timeout

300s

Liveness probe

HTTP 402