ToolVet
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Page Structured Changed

by Forest Web in Search & web

x402 APIPassing, checked 1 min ago

Detect meaningful changes in normalized static page metadata and JSON-LD with a deterministic semantic hash. Transport noise and malformed JSON-LD counts are excluded; callers can fetch full details with web.page-structured only when the state changes. Base mainnet USDC

POST https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/page/structured-changed

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Uptime
100%
Response time
46 ms typical, 265 ms slowest 5%
Last check
1 min ago
Next check
in 31 min

How to call it

POST https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/page/structured-changed

Each call costs $0.002 in USDC on Base, 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://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/page/structured-changed
content-type: application/json

{
  "previous_hash": "sha256:0000000000000000000000000000000000000000000000000000000000000000",
  "url": "https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/fixtures/page"
}

Parameters

ParameterTypeRequiredDescription
previous_hashstringNoEarlier result hash used to detect a material change.
urlstringYesPublic HTTP(S) URL to inspect, resolve, or compare.

Example response

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

{
  "capability": "web.page-structured-changed",
  "data": {
    "canonical_url": "example",
    "changed": false,
    "changed_fields": [],
    "entity_count": 0,
    "new_hash": "example",
    "previous_hash": "example",
    "rendered_javascript": false,
    "source_url": "example",
    "title": "example",
    "truncated": false,
    "type_counts": []
  },
  "meta": {
    "cache": "miss",
    "checked_at": "2026-01-01T00:00:00.000Z",
    "duration_ms": 0,
    "provider": "safe-http"
  },
  "ok": true,
  "version": "1"
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.002.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/page/structured-changed' \
  -H 'content-type: application/json' \
  --data-raw '{"previous_hash":"sha256:0000000000000000000000000000000000000000000000000000000000000000","url":"https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/fixtures/page"}'

# 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://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/page/structured-changed' \
  -H 'content-type: application/json' \
  --data-raw '{"previous_hash":"sha256:0000000000000000000000000000000000000000000000000000000000000000","url":"https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/fixtures/page"}' \
  | 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 $0.002 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.002" });
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 $0.002 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fhttp--forest-gas-station-mainnet--lcjl27p8lmjs.code.run%2Fpage%2Fstructured-changed&method=POST
const res = await pay("https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/page/structured-changed", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "previous_hash": "sha256:0000000000000000000000000000000000000000000000000000000000000000",
    "url": "https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/fixtures/page"
  }),
});
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 $0.002 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.002"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/page/structured-changed",
        json={
            "previous_hash": "sha256:0000000000000000000000000000000000000000000000000000000000000000",
            "url": "https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/fixtures/page",
        },
    )
    print(res.status_code, res.text)

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