ToolVet
78trust / 100

Run X402 Offer Check

by AISkills402: x402 Offer Check in Other

x402 APIPassing, checked 3 h ago

x402 Offer Check API: probes a public x402 storefront from the Cloudflare edge (GET, POST, OPTIONS) and reports what a buyer sees - payment-required header vs body, extra, bazaar, CORS, header size, 404 on the other method - as findings by severity. $0.01 USDC per check, a live measurement (a replayed payment header returns the receipt, not a new measurement). POST JSON {url, method?}; free example at https://api.aiskills402.com/v1/run/x402-offer-check/example

POST
https://api.aiskills402.com/v1/run/x402-offer-check
Price
$0.01
per call in USDC
Uptime
100%
last 30 days
Response time
182 ms
799 ms 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://api.aiskills402.com/v1/run/x402-offer-check

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://api.aiskills402.com/v1/run/x402-offer-check
content-type: application/json

{
  "method": "auto",
  "url": "https://api.aiskills402.com/v1/run/jsonl-repair"
}

Parameters

ParameterTypeRequiredDescription
methodstringNoWhich method to probe first; the other one is always probed too. One of: auto, GET, POST. Default: "auto".
urlstringYesPublic https address of the x402 resource to check (port 443, a DNS name; no IP addresses, no *.workers.dev).

Example response

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

Example response, 49 lines
{
  "engine": "1.0.0",
  "input_sha256": "<sha256 of the request>",
  "ok": true,
  "receipt": {
    "settled": true,
    "tx": "0x<settlement transaction>"
  },
  "refusal": null,
  "replay": false,
  "result": {
    "checked_at": "2026-10-16T17:05:07.800Z",
    "final_url": "https://api.aiskills402.com/v1/run/jsonl-repair",
    "findings": [],
    "measured_from": "recorded",
    "offer": {
      "amount_micro": "3000",
      "amount_usd": "0.003",
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "bazaar": "full",
      "extra": {
        "name": "USD Coin",
        "version": "2"
      },
      "max_timeout_seconds": 60,
      "network": "eip155:8453",
      "pay_to": "0x8e37022edcf0f21cf3c9f93fee9d4d32519f36f4",
      "resource_url": "https://api.aiskills402.com/v1/run/jsonl-repair",
      "scheme": "exact",
      "service_name": "AISkills402 API: JSONL Repair",
      "x402_version": 2
    },
    "paid_method": "POST",
    "payable_by_v2_client": true,
    "reachable": true,
    "sizes": {
      "body_bytes": 2351,
      "payment_required_chars": 3136,
      "response_headers_bytes": 3873
    },
    "status_by_probe": {
      "GET": 405,
      "OPTIONS": 204,
      "POST": 402
    },
    "url": "https://api.aiskills402.com/v1/run/jsonl-repair"
  },
  "skill": "x402-offer-check"
}

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://api.aiskills402.com/v1/run/x402-offer-check' \
  -H 'content-type: application/json' \
  --data-raw '{"method":"auto","url":"https://api.aiskills402.com/v1/run/jsonl-repair"}'

# 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://api.aiskills402.com/v1/run/x402-offer-check' \
  -H 'content-type: application/json' \
  --data-raw '{"method":"auto","url":"https://api.aiskills402.com/v1/run/jsonl-repair"}' \
  | 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%2Fapi.aiskills402.com%2Fv1%2Frun%2Fx402-offer-check&method=POST
const res = await pay("https://api.aiskills402.com/v1/run/x402-offer-check", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "method": "auto",
    "url": "https://api.aiskills402.com/v1/run/jsonl-repair"
  }),
});
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://api.aiskills402.com/v1/run/x402-offer-check",
        json={
            "method": "auto",
            "url": "https://api.aiskills402.com/v1/run/jsonl-repair",
        },
    )
    print(res.status_code, res.text)

Security scan

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Recent checks

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