15trust / 100

Eip712 Review

by Signature reviewer | Vextorium in Onchain & crypto

x402 APIFailing, checked 2 h ago

Explain an EIP-712 typed-data signature before signing it: x402/EIP-3009 payment authorizations, EIP-2612 permits, Permit2 and Seaport orders. Flags unlimited allowances, long validity and non-official tokens, and returns the exact hash to compare with your wallet.

POST

https://api.vextorium.com/v1/eip712-review

Price: $0.005; per call in USDC
Uptime: 0.0%; last 30 days
Response time: -; no timed checks yet
Last check: Failed; 2 h ago, next any minute now

Run a free test call How to call it

Reliability

All checks passedSome failedAll failedNot checked

Latest check failed 2 h ago: Amount "0.005" is not in atomic token units

Status and outage history · Atom feed · Watch with other listings

How to call it

POST https://api.vextorium.com/v1/eip712-review

Each call costs $0.005 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.vextorium.com/v1/eip712-review
content-type: application/json

{
  "signature_data": {
    "domain": {
      "chainId": 8453,
      "name": "USD Coin",
      "verifyingContract": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "version": "2"
    },
    "message": {
      "from": "0x1111111111111111111111111111111111111111",
      "nonce": "0xabababababababababababababababababababababababababababababababab",
      "to": "0x2222222222222222222222222222222222222222",
      "validAfter": "1790634093",
      "validBefore": "1790634453",
      "value": "10000"
    },
    "primaryType": "TransferWithAuthorization",
    "types": {
      "TransferWithAuthorization": [
        {
          "name": "from",
          "type": "address"
        },
        {
          "name": "to",
          "type": "address"
        },
        {
          "name": "value",
          "type": "uint256"
        },
        {
          "name": "validAfter",
          "type": "uint256"
        },
        {
          "name": "validBefore",
          "type": "uint256"
        },
        {
          "name": "nonce",
          "type": "bytes32"
        }
      ]
    }
  }
}

Parameters

Parameter	Type	Required	Description
`signature_data`	object	Yes	EIP-712 object as passed to eth_signTypedData_v4: domain, types, primaryType, message

Example response

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

{
  "alerts": [],
  "application": "USD Coin",
  "domain_separator": "0x02fa7265e7c5d81118673727957699e4d68f74cd74b7db77da710fe8a2c7834f",
  "hash_to_sign": "0x06a81ecc73b8782ba9eb12a8dabd4e939c996fdf315485be12b25b0272724806",
  "message_hash": "0xa77c7438121ad832f331edb2dd5a83d0eb089d6d9ebc14b26dc245ea9f447b32",
  "network": "Base",
  "note": "Compare 'hash_to_sign' with the one your wallet shows: if they match, you are signing exactly this.",
  "summary": {
    "action": "Authorize a payment (EIP-3009, the one x402 uses on EVM networks)",
    "amount": "0.01 USDC",
    "for": "0x2222222222222222222222222222222222222222",
    "since": "0x1111111111111111111111111111111111111111",
    "token": "USDC oficial",
    "valid_since": "2026-09-28 22:21 UTC",
    "valid_until": "2026-09-28 22:27 UTC"
  },
  "type": "TransferWithAuthorization",
  "verdict": "ok",
  "verifier_contract": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.005.

curl: see the payment challenge

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://api.vextorium.com/v1/eip712-review' \
  -H 'content-type: application/json' \
  --data-raw '{"signature_data":{"domain":{"chainId":8453,"name":"USD Coin","verifyingContract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","version":"2"},"message":{"from":"0x1111111111111111111111111111111111111111","nonce":"0xabababababababababababababababababababababababababababababababab","to":"0x2222222222222222222222222222222222222222","validAfter":"1790634093","validBefore":"1790634453","value":"10000"},"primaryType":"TransferWithAuthorization","types":{"TransferWithAuthorization":[{"name":"from","type":"address"},{"name":"to","type":"address"},{"name":"value","type":"uint256"},{"name":"validAfter","type":"uint256"},{"name":"validBefore","type":"uint256"},{"name":"nonce","type":"bytes32"}]}}}'

# 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.vextorium.com/v1/eip712-review' \
  -H 'content-type: application/json' \
  --data-raw '{"signature_data":{"domain":{"chainId":8453,"name":"USD Coin","verifyingContract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","version":"2"},"message":{"from":"0x1111111111111111111111111111111111111111","nonce":"0xabababababababababababababababababababababababababababababababab","to":"0x2222222222222222222222222222222222222222","validAfter":"1790634093","validBefore":"1790634453","value":"10000"},"primaryType":"TransferWithAuthorization","types":{"TransferWithAuthorization":[{"name":"from","type":"address"},{"name":"to","type":"address"},{"name":"value","type":"uint256"},{"name":"validAfter","type":"uint256"},{"name":"validBefore","type":"uint256"},{"name":"nonce","type":"bytes32"}]}}}' \
  | 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 $0.005 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.vextorium.com%2Fv1%2Feip712-review&method=POST
const res = await pay("https://api.vextorium.com/v1/eip712-review", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "signature_data": {
      "domain": {
        "chainId": 8453,
        "name": "USD Coin",
        "verifyingContract": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "version": "2"
      },
      "message": {
        "from": "0x1111111111111111111111111111111111111111",
        "nonce": "0xabababababababababababababababababababababababababababababababab",
        "to": "0x2222222222222222222222222222222222222222",
        "validAfter": "1790634093",
        "validBefore": "1790634453",
        "value": "10000"
      },
      "primaryType": "TransferWithAuthorization",
      "types": {
        "TransferWithAuthorization": [
          {
            "name": "from",
            "type": "address"
          },
          {
            "name": "to",
            "type": "address"
          },
          {
            "name": "value",
            "type": "uint256"
          },
          {
            "name": "validAfter",
            "type": "uint256"
          },
          {
            "name": "validBefore",
            "type": "uint256"
          },
          {
            "name": "nonce",
            "type": "bytes32"
          }
        ]
      }
    }
  }),
});
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 $0.005 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.post(
        "https://api.vextorium.com/v1/eip712-review",
        json={
            "signature_data": {
                "domain": {
                    "chainId": 8453,
                    "name": "USD Coin",
                    "verifyingContract": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
                    "version": "2",
                },
                "message": {
                    "from": "0x1111111111111111111111111111111111111111",
                    "nonce": "0xabababababababababababababababababababababababababababababababab",
                    "to": "0x2222222222222222222222222222222222222222",
                    "validAfter": "1790634093",
                    "validBefore": "1790634453",
                    "value": "10000",
                },
                "primaryType": "TransferWithAuthorization",
                "types": {
                    "TransferWithAuthorization": [
                        {
                            "name": "from",
                            "type": "address",
                        },
                        {
                            "name": "to",
                            "type": "address",
                        },
                        {
                            "name": "value",
                            "type": "uint256",
                        },
                        {
                            "name": "validAfter",
                            "type": "uint256",
                        },
                        {
                            "name": "validBefore",
                            "type": "uint256",
                        },
                        {
                            "name": "nonce",
                            "type": "bytes32",
                        },
                    ],
                },
            },
        },
    )
    print(res.status_code, res.text)

Security scan

No findings

We scan names, descriptions and tool definitions for hidden instructions and other prompt-injection patterns.

Recent checks

When	Result	HTTP	Time	Price
2 h ago	Amount "0.005" is not in atomic token units	402	262 ms	$0.005
8 h ago	Amount "0.005" is not in atomic token units	402	274 ms	$0.005
13 h ago	Amount "0.005" is not in atomic token units	402	94 ms	$0.005
18 h ago	Amount "0.005" is not in atomic token units	402	85 ms	$0.005
22 h ago	Amount "0.005" is not in atomic token units	402	274 ms	$0.005

Show 10 older checks

27 h ago	Amount "0.005" is not in atomic token units	402	285 ms	$0.005
32 h ago	Amount "0.005" is not in atomic token units	402	391 ms	$0.005
37 h ago	Amount "0.005" is not in atomic token units	402	98 ms	$0.005
41 h ago	Amount "0.005" is not in atomic token units	402	221 ms	$0.005
46 h ago	Amount "0.005" is not in atomic token units	402	246 ms	$0.005
2 days ago	Amount "0.005" is not in atomic token units	402	248 ms	$0.005
2 days ago	Amount "0.005" is not in atomic token units	402	358 ms	$0.005
3 days ago	Amount "0.005" is not in atomic token units	402	84 ms	$0.005
3 days ago	Amount "0.005" is not in atomic token units	402	79 ms	$0.005
3 days ago	Amount "0.005" is not in atomic token units	402	179 ms	$0.005

Trust score 15/ 100

Availability (30-day uptime)		0 / 30
Valid x402 challenge		0 / 15
Response time		0 / 10
Real paying agents (30 days)		5 / 15
Charges what it lists		0 / 10
Security scan		10 / 10
Verified owner		0 / 10

How the score works

Payment terms

Price: $0.005 per call
Listed at: $0.005
Token: USDC
Networks: Base, Solana, Optimism, eip155:5042
Pays to: 0xb9f0…1aCf

Real usage

Paying agents: 2 in 30 days
Paid calls: 2 in 30 days
Last paid call: 19 h ago

Source: x402 Bazaar settlement data.

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Trust score

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