ToolVet
78trust / 100

Preflight

by PennyAPI x402 Seller Preflight in Other

x402 APIPassing, checked 59 min ago

Preflight an unfamiliar x402 paid API before spending. Validate the live 402 payment challenge, network, USDC asset, amount, payTo recipient, TLS, redirects, manifest presence, latency, and provenance. Returns deterministic GO/REVIEW/STOP and never signs or sends payment to the inspected seller.

GET
https://pennyregwatch.com/v1/x402/preflight
Price
$0.001
per call in USDC
Uptime
100%
last 30 days
Response time
319 ms
424 ms slowest 5%
Last check
Passed
59 min 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

GET https://pennyregwatch.com/v1/x402/preflight

Each call costs $0.001 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.

GET https://pennyregwatch.com/v1/x402/preflight?url=https%3A%2F%2Fexample.com%2Fpaid-endpoint

Parameters

ParameterTypeRequiredDescription
urlstringYesExact public x402 endpoint URL to check before paying

Example response

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

{
  "decision": "GO",
  "http_status": 402,
  "ok": true,
  "source": {
    "payment_sent": false,
    "type": "live_unpaid_probe"
  },
  "target": "https://example.com/paid-endpoint",
  "x402": {
    "accepts_count": 1,
    "amount_atomic": "1000",
    "challenge_present": true,
    "network": "eip155:8453",
    "pay_to": "0x0000000000000000000000000000000000000001",
    "scheme": "exact",
    "x402_version": 2
  }
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.001.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://pennyregwatch.com/v1/x402/preflight?url=https%3A%2F%2Fexample.com%2Fpaid-endpoint'

# 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 - 'https://pennyregwatch.com/v1/x402/preflight?url=https%3A%2F%2Fexample.com%2Fpaid-endpoint' \
  | 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 $0.001 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.001" });
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 $0.001 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fpennyregwatch.com%2Fv1%2Fx402%2Fpreflight
const res = await pay("https://pennyregwatch.com/v1/x402/preflight?url=https%3A%2F%2Fexample.com%2Fpaid-endpoint");
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 $0.001 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.001"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://pennyregwatch.com/v1/x402/preflight?url=https%3A%2F%2Fexample.com%2Fpaid-endpoint")
    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
59 min agoPassed402426 ms$0.001
5 h agoPassed402321 ms$0.001
9 h agoPassed402374 ms$0.001
13 h agoPassed402399 ms$0.001
16 h agoPassed402412 ms$0.001
Show 10 older checks
20 h agoPassed402334 ms$0.001
24 h agoPassed402375 ms$0.001
27 h agoPassed402338 ms$0.001
30 h agoPassed402312 ms$0.001
33 h agoPassed402340 ms$0.001
36 h agoPassed402319 ms$0.001
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43 h agoPassed402297 ms$0.001
2 days agoPassed402351 ms$0.001
2 days agoPassed402308 ms$0.001