ToolVet
80trust / 100

Site Changed Since

by Forest Web in Developer tools

x402 APIPassing, checked 1 h ago

Detect bounded changes across one static page surface using one HTML fetch plus at most one robots.txt fetch. Forest hashes HTTP identity, page metadata, normalized JSON-LD, downloadable links, form schema and robots context without storing snapshots, rendering JavaScript or submitting anything. Base mainnet USDC

POST https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/site/changed-since

Last 30 days

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Status and outage history · Atom feed

Uptime
100%
Response time
41 ms typical, 189 ms slowest 5%
Last check
1 h ago
Next check
any minute now

How to call it

POST https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/site/changed-since

Each call costs $0.004 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/site/changed-since
content-type: application/json

{
  "url": "https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/fixtures/page",
  "user_agent": "ForestBot/1.0"
}

Parameters

ParameterTypeRequiredDescription
previous_dimensionsobjectNoPublic previous dimensions value used to scope this lookup.
previous_hashstringNoEarlier result hash used to detect a material change.
urlstringYesPublic HTTP(S) URL to inspect, resolve, or compare.
user_agentstringNoPublic user agent value used to scope this lookup.

Example response

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

Example response, 65 lines
{
  "capability": "web.site-changed-since",
  "data": {
    "changed": false,
    "changed_dimensions": [],
    "classification_complete": false,
    "dimension_hashes": {
      "downloads": "sha256:0000000000000000000000000000000000000000000000000000000000000000",
      "forms": "sha256:0000000000000000000000000000000000000000000000000000000000000000",
      "http": "sha256:0000000000000000000000000000000000000000000000000000000000000000",
      "page": "sha256:0000000000000000000000000000000000000000000000000000000000000000",
      "robots": "sha256:0000000000000000000000000000000000000000000000000000000000000000",
      "structured": "sha256:0000000000000000000000000000000000000000000000000000000000000000"
    },
    "downloads": {
      "count": 0,
      "format_counts": []
    },
    "forms": {
      "field_count": 0,
      "form_count": 0,
      "method_counts": []
    },
    "http": {
      "cache": {
        "cache_control": "example",
        "etag": "example",
        "last_modified": "example"
      },
      "content_type": "example",
      "status": 200
    },
    "new_hash": "sha256:0000000000000000000000000000000000000000000000000000000000000000",
    "page": {
      "canonical_url": "example",
      "description": "example",
      "language": "example",
      "title": "example"
    },
    "previous_hash": "example",
    "provider_request_budget": 2,
    "provider_request_count": 1,
    "rendered_javascript": false,
    "robots": {
      "decision": "allowed",
      "state": "available",
      "status": 1
    },
    "scope": "bounded_static_site_surface_plus_robots_only",
    "source_url": "example",
    "structured": {
      "entity_count": 0,
      "type_counts": []
    },
    "truncated": false
  },
  "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 $0.004.

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/site/changed-since' \
  -H 'content-type: application/json' \
  --data-raw '{"url":"https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/fixtures/page","user_agent":"ForestBot/1.0"}'

# 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/site/changed-since' \
  -H 'content-type: application/json' \
  --data-raw '{"url":"https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/fixtures/page","user_agent":"ForestBot/1.0"}' \
  | 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%2Fhttp--forest-gas-station-mainnet--lcjl27p8lmjs.code.run%2Fsite%2Fchanged-since&method=POST
const res = await pay("https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/site/changed-since", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "url": "https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/fixtures/page",
    "user_agent": "ForestBot/1.0"
  }),
});
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://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/site/changed-since",
        json={
            "url": "https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/fixtures/page",
            "user_agent": "ForestBot/1.0",
        },
    )
    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
1 h agoPassed40253 ms$0.004
5 h agoPassed402117 ms$0.004
10 h agoPassed402114 ms$0.004
13 h agoPassed402150 ms$0.004
17 h agoPassed40237 ms$0.004
21 h agoPassed40242 ms$0.004
25 h agoPassed40237 ms$0.004
29 h agoPassed40239 ms$0.004
32 h agoPassed40241 ms$0.004
36 h agoPassed40266 ms$0.004
39 h agoPassed402209 ms$0.004
43 h agoPassed402189 ms$0.004
46 h agoPassed40253 ms$0.004
2 days agoPassed40239 ms$0.004
2 days agoPassed40239 ms$0.004