Inspect

{
  "charged_usd": 0.005,
  "checks": 11,
  "ok": true,
  "passed": 11,
  "receipt": {
    "charter": "https://api.s2ar.dev/charter",
    "cost_usd": 0.005,
    "determinism": "replayable",
    "evidence_hash": "sha256:94abfed2…",
    "issued_at": "2026-10-10T00:00:00Z",
    "refund_rule": "failed calls are never charged",
    "what": "…",
    "witnesses": [
      "sym"
    ]
  },
  "record_sha256": "7a0c…",
  "results": [
    {
      "check": "answers_402",
      "evidence": {
        "status": 402
      },
      "ok": true
    },
    {
      "check": "cdp_validate",
      "evidence": {
        "simulation": "accepted",
        "valid": true
      },
      "ok": true
    }
  ],
  "score": 1,
  "status": 402,
  "summary": {
    "declared_method": "GET",
    "networks": [
      "base"
    ],
    "price_usd": 0.005
  },
  "verdict": "pass"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://api.s2ar.dev/x402/v1/x402/inspect?method=GET&resource=https%3A%2F%2Fapi.s2ar.dev%2Fx402%2Fv1%2Fassert'

# 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://api.s2ar.dev/x402/v1/x402/inspect?method=GET&resource=https%3A%2F%2Fapi.s2ar.dev%2Fx402%2Fv1%2Fassert' \
  | 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 $0.005 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.005" });
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 $0.005 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fapi.s2ar.dev%2Fx402%2Fv1%2Fx402%2Finspect
const res = await pay("https://api.s2ar.dev/x402/v1/x402/inspect?method=GET&resource=https%3A%2F%2Fapi.s2ar.dev%2Fx402%2Fv1%2Fassert");
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 $0.005 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.005"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://api.s2ar.dev/x402/v1/x402/inspect?method=GET&resource=https%3A%2F%2Fapi.s2ar.dev%2Fx402%2Fv1%2Fassert")
    print(res.status_code, res.text)