ToolVet
78trust / 100

Payments Challenge Sanity

by x402 Challenge Policy Check in Security & trust

x402 APIPassing, checked 3 h ago

Validate an x402 payment declaration before signing. Check a caller-supplied challenge against expected resource, network, asset, payee and exact spending limits; return mismatches and an integrity receipt. Offline only: no endpoint probe, uptime history, settlement test, safety clearance or payment authorization. New modular adapter: retained result recovery for 24 hours, minimal receipt metadata for 90 days. Existing live route unchanged.

POST
https://www.mahastrategies.com/api/v1/verify/payments/challenge-sanity
Price
$0.01
per call in USDC
Uptime
100%
last 30 days
Response time
184 ms
184 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

How to call it

POST https://www.mahastrategies.com/api/v1/verify/payments/challenge-sanity

Each call costs $0.010022 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://www.mahastrategies.com/api/v1/verify/payments/challenge-sanity
content-type: application/json

{
  "challenge": {
    "amountBaseUnits": "10000",
    "asset": "0x1111111111111111111111111111111111111111",
    "maxTimeoutSeconds": 60,
    "network": "eip155:8453",
    "payee": "0x1111111111111111111111111111111111111111",
    "resourceUrl": "https://example.org/result",
    "scheme": "exact",
    "version": 2
  },
  "dataClass": "synthetic",
  "expected": {
    "asset": "0x1111111111111111111111111111111111111111",
    "maxAmountBaseUnits": "10000",
    "network": "eip155:8453",
    "payee": "0x1111111111111111111111111111111111111111",
    "resourceUrl": "https://example.org/result"
  }
}

Parameters

ParameterTypeRequiredDescription
challengeobjectYes
dataClassstringYes One of: public, synthetic.
expectedobjectYes

Example response

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

{
  "data": {
    "chargedAmount": "10022",
    "inputHash": "sha256:0f2f32610c46537b318d31712df444db18cc48b352bcb6b56b09860e5…",
    "limitations": [
      "Public or synthetic inputs only. Caller labels are declarations,…"
    ],
    "productId": "x402-challenge-sanity",
    "result": {
      "consistent": true,
      "executionAuthorized": false,
      "issues": [],
      "liveServerVerified": false
    },
    "resultHash": "sha256:354c172124629f38f7de9ceba0779cff39d730edf63edea2a18445a04…",
    "sourceContractAmount": "3500",
    "version": "maha-legacy-adapter/1"
  },
  "proof": {
    "settlement_id": "0x00000000000000000000000000000000000000000000000000000000000000…"
  },
  "success": 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 $0.010022.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://www.mahastrategies.com/api/v1/verify/payments/challenge-sanity' \
  -H 'content-type: application/json' \
  --data-raw '{"challenge":{"amountBaseUnits":"10000","asset":"0x1111111111111111111111111111111111111111","maxTimeoutSeconds":60,"network":"eip155:8453","payee":"0x1111111111111111111111111111111111111111","resourceUrl":"https://example.org/result","scheme":"exact","version":2},"dataClass":"synthetic","expected":{"asset":"0x1111111111111111111111111111111111111111","maxAmountBaseUnits":"10000","network":"eip155:8453","payee":"0x1111111111111111111111111111111111111111","resourceUrl":"https://example.org/result"}}'

# 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://www.mahastrategies.com/api/v1/verify/payments/challenge-sanity' \
  -H 'content-type: application/json' \
  --data-raw '{"challenge":{"amountBaseUnits":"10000","asset":"0x1111111111111111111111111111111111111111","maxTimeoutSeconds":60,"network":"eip155:8453","payee":"0x1111111111111111111111111111111111111111","resourceUrl":"https://example.org/result","scheme":"exact","version":2},"dataClass":"synthetic","expected":{"asset":"0x1111111111111111111111111111111111111111","maxAmountBaseUnits":"10000","network":"eip155:8453","payee":"0x1111111111111111111111111111111111111111","resourceUrl":"https://example.org/result"}}' \
  | 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 $0.010022 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.010022" });
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 $0.010022 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fwww.mahastrategies.com%2Fapi%2Fv1%2Fverify%2Fpayments%2Fchallenge-sanity&method=POST
const res = await pay("https://www.mahastrategies.com/api/v1/verify/payments/challenge-sanity", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "challenge": {
      "amountBaseUnits": "10000",
      "asset": "0x1111111111111111111111111111111111111111",
      "maxTimeoutSeconds": 60,
      "network": "eip155:8453",
      "payee": "0x1111111111111111111111111111111111111111",
      "resourceUrl": "https://example.org/result",
      "scheme": "exact",
      "version": 2
    },
    "dataClass": "synthetic",
    "expected": {
      "asset": "0x1111111111111111111111111111111111111111",
      "maxAmountBaseUnits": "10000",
      "network": "eip155:8453",
      "payee": "0x1111111111111111111111111111111111111111",
      "resourceUrl": "https://example.org/result"
    }
  }),
});
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 $0.010022 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.010022"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://www.mahastrategies.com/api/v1/verify/payments/challenge-sanity",
        json={
            "challenge": {
                "amountBaseUnits": "10000",
                "asset": "0x1111111111111111111111111111111111111111",
                "maxTimeoutSeconds": 60,
                "network": "eip155:8453",
                "payee": "0x1111111111111111111111111111111111111111",
                "resourceUrl": "https://example.org/result",
                "scheme": "exact",
                "version": 2,
            },
            "dataClass": "synthetic",
            "expected": {
                "asset": "0x1111111111111111111111111111111111111111",
                "maxAmountBaseUnits": "10000",
                "network": "eip155:8453",
                "payee": "0x1111111111111111111111111111111111111111",
                "resourceUrl": "https://example.org/result",
            },
        },
    )
    print(res.status_code, res.text)

Security scan

No findings

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Recent checks

WhenResultHTTPTimePrice
3 h agoPassed402210 ms$0.01
13 h agoPassed402184 ms$0.01