ToolVet
80trust / 100

Page Change

by Page change detection in Search & web

x402 APIPassing, checked 2 h ago

Tell whether a public web page changed since you last looked, with nothing stored on this side. One fetch (15 s, 2 MB) takes the text a reader sees (hidden elements, scripts and styles dropped; a CSS selector narrows it to one region), collapses whitespace, strips any ignore entries (a literal substring, or /pattern/ for a regex, for timestamps and counters), and answers a sha256 fingerprint of that text with the origin's ETag and Last-Modified.

POST
https://agent402.tools/api/page-change
Price
$0.004
per call in USDC
Uptime
100%
last 30 days
Response time
272 ms
1.1 s slowest 5%
Last check
Passed
2 h ago, next any minute now

Run a free test callHow to call it

Reliability

All checks passedSome failedAll failedNot checked

Status and outage history · Atom feed · Watch with other listings

How to call it

POST https://agent402.tools/api/page-change

Each call costs $0.004 in USDC on Polygon, paid with the request over x402.

Run a free test callOne unpaid request, the way an agent sends it. You see the payment challenge it gets back. Nothing is charged.

Example request

From the listing.

POST https://agent402.tools/api/page-change
content-type: application/json

{
  "url": "https://agent402.tools/guides/x402-in-5-minutes"
}

Parameters

ParameterTypeRequiredDescription
baselineobjectNo
ignorearray of stringNo
includeTextbooleanNo
selectorstringNo
urlstringYes

Example response

The provider's example. We can't check it without paying.

{
  "algorithm": "sha256",
  "changed": null,
  "contentType": "text/html; charset=utf-8",
  "etag": "W/\"139af-U5t4XcoenUVzgZ16Boysd1XPlc0\"",
  "fetchedAt": "2026-10-20T16:40:31.472Z",
  "fingerprint": "4bd9ae84b63fc48e64e2f63e231dcfd12e5492383fc407f23897b18faa1a25fe",
  "ignored": 0,
  "lastModified": null,
  "length": 5038,
  "lines": 96,
  "requestedUrl": "https://agent402.tools/guides/x402-in-5-minutes",
  "selector": null,
  "selectorMatches": null,
  "textTruncated": false,
  "title": "Make your AI agent pay for what it needs: x402 in 5 minutes",
  "url": "https://agent402.tools/guides/x402-in-5-minutes"
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.004.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://agent402.tools/api/page-change' \
  -H 'content-type: application/json' \
  --data-raw '{"url":"https://agent402.tools/guides/x402-in-5-minutes"}'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - -X POST 'https://agent402.tools/api/page-change' \
  -H 'content-type: application/json' \
  --data-raw '{"url":"https://agent402.tools/guides/x402-in-5-minutes"}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode
JavaScript: pay and call
// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.004 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.004" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.004 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fagent402.tools%2Fapi%2Fpage-change&method=POST
const res = await pay("https://agent402.tools/api/page-change", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "url": "https://agent402.tools/guides/x402-in-5-minutes"
  }),
});
console.log(res.status, await res.text());
Python: pay and call
# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.004 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.004"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://agent402.tools/api/page-change",
        json={
            "url": "https://agent402.tools/guides/x402-in-5-minutes",
        },
    )
    print(res.status_code, res.text)

Security scan

No findings

We scan names, descriptions and tool definitions for hidden instructions and other prompt-injection patterns.

Recent checks

WhenResultHTTPTimePrice
2 h agoPassed402210 ms$0.004
6 h agoPassed402341 ms$0.004
11 h agoPassed402198 ms$0.004
16 h agoPassed402320 ms$0.004
20 h agoPassed402316 ms$0.004
Show 7 older checks
25 h agoPassed402304 ms$0.004
29 h agoPassed402191 ms$0.004
33 h agoPassed402272 ms$0.004
37 h agoPassed402272 ms$0.004
41 h agoPassed402324 ms$0.004
45 h agoPassed402258 ms$0.004
2 days agoPassed4021.1 s$0.004