Monitoring · x402 · early usage

Website uptime and change check: is this URL up right now, and has the page changed

by 402oracle.com · discovered, not yet claimed by its owner · updated 2026-10-11

30d calls8

30d payers5

MethodPOST

Outputjson

Mirrored from Coinbase's public x402 Bazaar. The description is the provider's own text and has not been reviewed here; the payment requirements are copied as published.

What it does

Website uptime and change check: is this URL up right now, and has the page changed? Fetches the URL and returns the HTTP status, Last-Modified and ETag headers, a SHA-256 fingerprint of the content, and whether it changed versus a hash you pass in. Use it to check a site is live, detect stale data, monitor a page for changes, or decide whether to invalidate a cache before your agent acts on what it says. Returns a signed attestation.

Tags: uptime-check · website-monitoring · change-detection · stale-data · url-check · bazaar

Call contract

Method: POST
Input: json
Output: json
Last paid call: 2026-10-11

Input example from Bazaar metadata

{
  "url": "https://example.com/data.json"
}

Output example

{
  "attestation": {
    "confidence": 0.98,
    "result": {
      "changed": false,
      "content_sha256": "9f86d081884c7d65",
      "reachable": true,
      "status": 200
    },
    "subject": {
      "url": "https://example.com/data.json"
    },
    "type": "freshness_verification"
  },
  "signature": {
    "alg": "ES256",
    "jwks": "/.well-known/jwks.json"
  }
}

Use with an agent

Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
Inspect. Fetch /resources/27106.json for the price and payment options.
Pay. Call GET https://402oracle.com/verify/freshness. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
Execute. The provider returns 200 with the data. Agent Bazaar is not in the request path and never sees your payment.

For humans

You don't need an account or an API key; you need a wallet holding a small amount of USDC on Base, Polygon, Arbitrum One, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price: $0.02 / request
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: Base, Polygon, Arbitrum One
Demand: 8 calls · 5 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	Base eip155:8453	USDC	$0.02	0x7a19cd388c7f69145fef09b960853e0a429b6f4a	300s
exact	Polygon eip155:137	USDC	$0.02	0x7a19cd388c7f69145fef09b960853e0a429b6f4a	300s
exact	Arbitrum One eip155:42161	USDC	$0.02	0x7a19cd388c7f69145fef09b960853e0a429b6f4a	300s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0x7a19cd388c7f69145fef09b960853e0a429b6f4a",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "20000",
    "amountUsd": 0.02,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:137",
    "payTo": "0x7a19cd388c7f69145fef09b960853e0a429b6f4a",
    "asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
    "amount": "20000",
    "amountUsd": 0.02,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:42161",
    "payTo": "0x7a19cd388c7f69145fef09b960853e0a429b6f4a",
    "asset": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
    "amount": "20000",
    "amountUsd": 0.02,
    "maxTimeoutSeconds": 300
  }
]

Schemas

Output schema (JSON Schema)

{
  "properties": {
    "example": {
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}

Example shape — generated from the schema, not a captured live response

{
  "example": {},
  "type": "string"
}

Examples

curl

curl "https://402oracle.com/verify/freshness"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

JavaScript

const res = await fetch("https://402oracle.com/verify/freshness");
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

Python

import httpx
res = httpx.get("https://402oracle.com/verify/freshness")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header

Details

Provider: 402oracle.com
Endpoint: https://402oracle.com/verify/freshness
Machine-readable: /resources/27106.json