Check

{
  "action": "Use repaired.content (auto-fixed JSON) or retry the source.",
  "check_version": "dq-0.1.0",
  "detected_type": "json",
  "issues": [
    {
      "code": "json_invalid",
      "message": "Not valid JSON: Unexpected token '`', \"```json\n{\"\"... is not valid JSON",
      "severity": "critical"
    },
    {
      "code": "placeholder_values",
      "message": "Placeholder-looking values (N/A, TODO, lorem ipsum, \"string\"...) at: sku",
      "severity": "minor"
    }
  ],
  "quality_score": 32,
  "repaired": {
    "content": "{\"name\": \"Acme Widget\", \"price\": 12.5, \"tags\": [\"tools\", \"home\"], \"sku\": \"N/A\"}",
    "note": "Mechanical repair only; check the steps (a closed truncation means data is missing).",
    "steps": [
      "removed markdown code fence",
      "removed trailing commas"
    ]
  },
  "tags": [
    "invalid_json",
    "repairable",
    "placeholder"
  ],
  "usable": false,
  "verdict": "fail"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://seenly-payload-check.vercel.app/api/check?content=%60%60%60json%0A%7B%22name%22%3A+%22Acme+Widget%22%2C+%22price%22%3A+12.5%2C+%22tags%22%3A+%5B%22tools%22%2C+%22home%22%2C%5D%2C+%22sku%22%3A+%22N%2FA%22%7D%0A%60%60%60&expect=auto'

# 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://seenly-payload-check.vercel.app/api/check?content=%60%60%60json%0A%7B%22name%22%3A+%22Acme+Widget%22%2C+%22price%22%3A+12.5%2C+%22tags%22%3A+%5B%22tools%22%2C+%22home%22%2C%5D%2C+%22sku%22%3A+%22N%2FA%22%7D%0A%60%60%60&expect=auto' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// 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 $0.03 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.03" });
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 $0.03 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fseenly-payload-check.vercel.app%2Fapi%2Fcheck
const res = await pay("https://seenly-payload-check.vercel.app/api/check?content=%60%60%60json%0A%7B%22name%22%3A+%22Acme+Widget%22%2C+%22price%22%3A+12.5%2C+%22tags%22%3A+%5B%22tools%22%2C+%22home%22%2C%5D%2C+%22sku%22%3A+%22N%2FA%22%7D%0A%60%60%60&expect=auto");
console.log(res.status, await res.text());

# 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 $0.03 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.03"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://seenly-payload-check.vercel.app/api/check?content=%60%60%60json%0A%7B%22name%22%3A+%22Acme+Widget%22%2C+%22price%22%3A+12.5%2C+%22tags%22%3A+%5B%22tools%22%2C+%22home%22%2C%5D%2C+%22sku%22%3A+%22N%2FA%22%7D%0A%60%60%60&expect=auto")
    print(res.status_code, res.text)