ToolVet
16trust / 100

Siwe Verify

by Vextorium in Onchain & crypto

x402 APIFailing, checked 3 h ago

Verify a Sign-In with Ethereum (EIP-4361) login: parses domain, address, chain, nonce and dates, checks the signature and expiry, and optionally the expected domain and nonce. Authenticate users or agents by wallet.

POST https://api.vextorium.com/v1/siwe-verify

Last 30 days

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Status and outage history · Atom feed

Uptime
0.0%
Response time
- typical, - slowest 5%
Last check
3 h ago: Amount "0.003" is not in atomic token units
Next check
any minute now

How to call it

POST https://api.vextorium.com/v1/siwe-verify

Each call costs $0.003 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/siwe-verify
content-type: application/json

{
  "message": "example.com wants you to sign in with your Ethereum account:\n0x7E5F4552091A69125d5DfCb7b8C2659029395Bdf\n\nSign in\n\nURI: https://example.com\nVersion: 1\nChain ID: 8453\nNonce: abc12345\nIssued At: 2026-10-02T20:00:00Z",
  "signature": "0xcc7863e87c5879d5fd0bb7b2bc925ec0f86f59a07badb05d8faffec9b061d18a6227988b56b1e18b7a0603d034a7c5b378f5b039e0af9c929bf090ded43dd5941c"
}

Parameters

ParameterTypeRequiredDescription
domainstringNo
messagestringYes
noncestringNo
signaturestringYes

Example response

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

{
  "address": "0x7E5F4552091A69125d5DfCb7b8C2659029395Bdf",
  "chain": "8453",
  "domain": "example.com",
  "errors": [],
  "expires": null,
  "issued": "2026-10-02T20:00:00Z",
  "nonce": "abc12345",
  "statement": "Sign in",
  "uri": "https://example.com",
  "valid": 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 $0.003.

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/siwe-verify' \
  -H 'content-type: application/json' \
  --data-raw '{"message":"example.com wants you to sign in with your Ethereum account:\n0x7E5F4552091A69125d5DfCb7b8C2659029395Bdf\n\nSign in\n\nURI: https://example.com\nVersion: 1\nChain ID: 8453\nNonce: abc12345\nIssued At: 2026-10-02T20:00:00Z","signature":"0xcc7863e87c5879d5fd0bb7b2bc925ec0f86f59a07badb05d8faffec9b061d18a6227988b56b1e18b7a0603d034a7c5b378f5b039e0af9c929bf090ded43dd5941c"}'

# 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/siwe-verify' \
  -H 'content-type: application/json' \
  --data-raw '{"message":"example.com wants you to sign in with your Ethereum account:\n0x7E5F4552091A69125d5DfCb7b8C2659029395Bdf\n\nSign in\n\nURI: https://example.com\nVersion: 1\nChain ID: 8453\nNonce: abc12345\nIssued At: 2026-10-02T20:00:00Z","signature":"0xcc7863e87c5879d5fd0bb7b2bc925ec0f86f59a07badb05d8faffec9b061d18a6227988b56b1e18b7a0603d034a7c5b378f5b039e0af9c929bf090ded43dd5941c"}' \
  | 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 $0.003 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.003" });
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 $0.003 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fapi.vextorium.com%2Fv1%2Fsiwe-verify&method=POST
const res = await pay("https://api.vextorium.com/v1/siwe-verify", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "message": "example.com wants you to sign in with your Ethereum account:\n0x7E5F4552091A69125d5DfCb7b8C2659029395Bdf\n\nSign in\n\nURI: https://example.com\nVersion: 1\nChain ID: 8453\nNonce: abc12345\nIssued At: 2026-10-02T20:00:00Z",
    "signature": "0xcc7863e87c5879d5fd0bb7b2bc925ec0f86f59a07badb05d8faffec9b061d18a6227988b56b1e18b7a0603d034a7c5b378f5b039e0af9c929bf090ded43dd5941c"
  }),
});
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 $0.003 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.003"})
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/siwe-verify",
        json={
            "message": "example.com wants you to sign in with your Ethereum account:\n0x7E5F4552091A69125d5DfCb7b8C2659029395Bdf\n\nSign in\n\nURI: https://example.com\nVersion: 1\nChain ID: 8453\nNonce: abc12345\nIssued At: 2026-10-02T20:00:00Z",
            "signature": "0xcc7863e87c5879d5fd0bb7b2bc925ec0f86f59a07badb05d8faffec9b061d18a6227988b56b1e18b7a0603d034a7c5b378f5b039e0af9c929bf090ded43dd5941c",
        },
    )
    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

WhenResultHTTPTimePrice
3 h agoAmount "0.003" is not in atomic token units40284 ms$0.003
7 h agoAmount "0.003" is not in atomic token units40280 ms$0.003
11 h agoAmount "0.003" is not in atomic token units40279 ms$0.003
16 h agoAmount "0.003" is not in atomic token units40277 ms$0.003
20 h agoAmount "0.003" is not in atomic token units40299 ms$0.003
24 h agoAmount "0.003" is not in atomic token units402115 ms$0.003
28 h agoAmount "0.003" is not in atomic token units40277 ms$0.003
32 h agoAmount "0.003" is not in atomic token units40277 ms$0.003
36 h agoAmount "0.003" is not in atomic token units40275 ms$0.003
40 h agoAmount "0.003" is not in atomic token units402165 ms$0.003
44 h agoAmount "0.003" is not in atomic token units40287 ms$0.003
2 days agoAmount "0.003" is not in atomic token units402178 ms$0.003
2 days agoAmount "0.003" is not in atomic token units402301 ms$0.003
2 days agoAmount "0.003" is not in atomic token units40275 ms$0.003
3 days agoAmount "0.003" is not in atomic token units40287 ms$0.003