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": "Answers how stale each oracle price actually is on Base right now, and whether a standard consumer staleness guard would reject it. Reads Chainlink's aggregator proxy and Pyth's on-chain price for the same asset in the same block, and reports each feed's age against a per-feed bound derived from its own measured update cadence -- not one global threshold, because those cadences differ by more than an order of magnitude on the same chain (Chainlink's USDC/USD on Base runs a 24-hour heartbeat by design, while ETH/USD updates in minutes). Why pay instead of reading it yourself: the trap is not fetching a price, it is knowing which address is the real proxy (a raw aggregator answers description() identically and then silently freezes when Chainlink rotates it) and what 'stale' means for that specific feed. The Chainlink-vs-Pyth spread is included, but always next to Pyth's own confidence interval, so a difference inside the oracle's stated uncertainty is not mistaken for disagreement. Optional assets query parameter; all supported assets by default.",
  "asset": "USDC",
  "error": "payment_required",
  "price": "$0.003",
  "accepts": [
    {
      "payTo": "0x63bc58472a8449eDd1d1af0B0c03cFc7c832Da2f",
      "price": "$0.003",
      "scheme": "exact",
      "network": "eip155:8453"
    },
    {
      "payTo": "0x63bc58472a8449eDd1d1af0B0c03cFc7c832Da2f",
      "price": {
        "asset": "0xfde4C96c8593536E31F229ea8F37b2Ada2699bb2",
        "extra": {
          "assetTransferMethod": "permit2"
        },
        "amount": "3000"
      },
      "scheme": "exact",
      "network": "eip155:8453"
    },
    {
      "payTo": "0x63bc58472a8449eDd1d1af0B0c03cFc7c832Da2f",
      "price": {
        "asset": "0x50c5725949A6F0c72E6C4a641F24049A917DB0Cb",
        "extra": {
          "supportsEip2612": true,
          "assetTransferMethod": "permit2"
        },
        "amount": "3000000000000000"
      },
      "scheme": "exact",
      "network": "eip155:8453"
    }
  ],
  "example": "https://api402x.com/oracle-staleness?assets=ETH%2FUSD%2CBTC%2FUSD",
  "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/oracle-staleness/preview",
  "authoritative": "payment-required header; this body is a duplicate for clients that read the body",
  "response_schema": "https://api402x.com/openapi.json — the full JSON Schema for this response. It is not repeated in the payment-required header because response headers have a hard 16 KB limit in common HTTP clients and this response is large. The header still carries a complete worked example of the shape."
}

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": "3000",
    "scheme": "exact",
    "network": "eip155:8453",
    "maxTimeoutSeconds": 300
  }
]

Provenance

Seen in the source catalog

2026-08-20 23:44Z

Last indexed by Roundhouse

2026-09-21 22:15Z

Last enriched (probe, favicon, geo)

2026-09-16 03:15Z

x402 version

2

Max timeout

300s

Liveness probe

HTTP 402