ToolVet
77trust / 100

Payment Guard

by Anyway Possible Payment Guard in Security & trust

x402 APIPassing, checked 3 h ago

Verify an x402 purchase before an AI agent signs. Validate the live HTTP 402 challenge, Base network, USDC asset, quoted price, recipient, price ceiling, buyer funding, optional gas reserve, and destination hazards, then receive a machine-readable safe-to-sign, fund, review, or reject decision. No account or API key.

POST
https://anywaypossible.com/api/payment-guard
Price
$0.01
per call in USDC
Uptime
100%
last 30 days
Response time
484 ms
2.5 s slowest 5%
Last check
Passed
3 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://anywaypossible.com/api/payment-guard

Each call costs $0.01 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://anywaypossible.com/api/payment-guard
content-type: application/json

{
  "expectedPayTo": "0x2222222222222222222222222222222222222222",
  "maxAmountUsdc": "0.10",
  "minGasReserveEth": "0",
  "payerAddress": "0x1111111111111111111111111111111111111111",
  "serviceUrl": "https://example.com/api/report"
}

Parameters

ParameterTypeRequiredDescription
expectedPayTostringNo
maxAmountUsdcstringYes
minGasReserveEthstringNo
payerAddressstringYes
serviceUrlstring (uri)Yes

Example response

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

{
  "alerts": [],
  "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  "checks": [
    {
      "id": "x402_contract",
      "status": "pass"
    }
  ],
  "decision": "safe_to_sign",
  "network": "eip155:8453",
  "quotedAmountUsdc": "0.01",
  "quotedPayTo": "0x2222222222222222222222222222222222222222",
  "recommendedAction": "Sign only the validated payment requirements.",
  "riskLevel": "low",
  "safeToSign": true
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.01.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://anywaypossible.com/api/payment-guard' \
  -H 'content-type: application/json' \
  --data-raw '{"expectedPayTo":"0x2222222222222222222222222222222222222222","maxAmountUsdc":"0.10","minGasReserveEth":"0","payerAddress":"0x1111111111111111111111111111111111111111","serviceUrl":"https://example.com/api/report"}'

# 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://anywaypossible.com/api/payment-guard' \
  -H 'content-type: application/json' \
  --data-raw '{"expectedPayTo":"0x2222222222222222222222222222222222222222","maxAmountUsdc":"0.10","minGasReserveEth":"0","payerAddress":"0x1111111111111111111111111111111111111111","serviceUrl":"https://example.com/api/report"}' \
  | 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 $0.01 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.01" });
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 $0.01 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fanywaypossible.com%2Fapi%2Fpayment-guard&method=POST
const res = await pay("https://anywaypossible.com/api/payment-guard", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "expectedPayTo": "0x2222222222222222222222222222222222222222",
    "maxAmountUsdc": "0.10",
    "minGasReserveEth": "0",
    "payerAddress": "0x1111111111111111111111111111111111111111",
    "serviceUrl": "https://example.com/api/report"
  }),
});
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 $0.01 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.01"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://anywaypossible.com/api/payment-guard",
        json={
            "expectedPayTo": "0x2222222222222222222222222222222222222222",
            "maxAmountUsdc": "0.10",
            "minGasReserveEth": "0",
            "payerAddress": "0x1111111111111111111111111111111111111111",
            "serviceUrl": "https://example.com/api/report",
        },
    )
    print(res.status_code, res.text)

Security scan

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