ToolVet
10trust / 100

Calldata Decode

by Lumen Agent Utilities in Onchain & crypto

x402 APIFailing, checked 4 h ago

Use when you hold raw EVM calldata and need to know what function it calls: returns selector, matching signatures (built-in + openchain/4byte) and ABI-decoded args for each candidate; unknown selectors return signaturesFound:0 instead of an error. Optional {signature} override. Example: 0xa9059cbb… -> transfer(address,uint256) with args. $0.002, no signup; not charged if the call errors.

POST
https://lumenworks-x402-decoder.onrender.com/v1/calldata/decode
Price
$0.002
per call in USDC
Uptime
0.0%
last 30 days
Response time
-
no timed checks yet
Last check
Failed
4 h ago, next in 3 days

Run a free test callHow to call it

Reliability

All checks passedSome failedAll failedNot checked

Latest check failed 4 h ago: Expected HTTP 402, got 404

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

How to call it

POST https://lumenworks-x402-decoder.onrender.com/v1/calldata/decode

Each call costs $0.002 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://lumenworks-x402-decoder.onrender.com/v1/calldata/decode
content-type: application/json

{
  "data": "0xa9059cbb000000000000000000000000ee9790cb3960952f585379f831a89b4e00b4029a00000000000000000000000000000000000000000000000000000000000f4240"
}

Parameters

ParameterTypeRequiredDescription
datastringYesCalldata hex starting with the 4-byte selector (0x…)
signaturestringNoOptional function signature override, e.g. transfer(address,uint256)

Example response

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

{
  "candidates": [
    {
      "args": [
        "0xee9790cB3960952F585379F831a89b4e00B4029A",
        "1000000"
      ],
      "signature": "transfer(address,uint256)"
    }
  ],
  "decoded": {
    "args": [
      "0xee9790cB3960952F585379F831a89b4e00B4029A",
      "1000000"
    ],
    "signature": "transfer(address,uint256)"
  },
  "selector": "0xa9059cbb",
  "signaturesFound": 1,
  "source": "openchain/4byte"
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.002.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://lumenworks-x402-decoder.onrender.com/v1/calldata/decode' \
  -H 'content-type: application/json' \
  --data-raw '{"data":"0xa9059cbb000000000000000000000000ee9790cb3960952f585379f831a89b4e00b4029a00000000000000000000000000000000000000000000000000000000000f4240"}'

# 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://lumenworks-x402-decoder.onrender.com/v1/calldata/decode' \
  -H 'content-type: application/json' \
  --data-raw '{"data":"0xa9059cbb000000000000000000000000ee9790cb3960952f585379f831a89b4e00b4029a00000000000000000000000000000000000000000000000000000000000f4240"}' \
  | 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 $0.002 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.002" });
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 $0.002 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Flumenworks-x402-decoder.onrender.com%2Fv1%2Fcalldata%2Fdecode&method=POST
const res = await pay("https://lumenworks-x402-decoder.onrender.com/v1/calldata/decode", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "data": "0xa9059cbb000000000000000000000000ee9790cb3960952f585379f831a89b4e00b4029a00000000000000000000000000000000000000000000000000000000000f4240"
  }),
});
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 $0.002 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.002"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://lumenworks-x402-decoder.onrender.com/v1/calldata/decode",
        json={
            "data": "0xa9059cbb000000000000000000000000ee9790cb3960952f585379f831a89b4e00b4029a00000000000000000000000000000000000000000000000000000000000f4240",
        },
    )
    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
4 h agoExpected HTTP 402, got 404404215 ms-
3 days agoExpected HTTP 402, got 404404254 ms-
4 days agoExpected HTTP 402, got 404404233 ms-
4 days agoExpected HTTP 402, got 404404219 ms-
4 days agoExpected HTTP 402, got 404404236 ms-
Show 10 older checks
4 days agoExpected HTTP 402, got 404404244 ms-
4 days agoExpected HTTP 402, got 404404231 ms-
5 days agoExpected HTTP 402, got 404404206 ms-
5 days agoExpected HTTP 402, got 404404248 ms-
5 days agoExpected HTTP 402, got 404404199 ms-
5 days agoExpected HTTP 402, got 404404218 ms-
5 days agoExpected HTTP 402, got 404404198 ms-
5 days agoExpected HTTP 402, got 404404281 ms-
6 days agoExpected HTTP 402, got 404404216 ms-
6 days agoExpected HTTP 402, got 404404223 ms-