ToolVet
80trust / 100

Transfer Authorization

by Build USDC transfer in Onchain & crypto

x402 APIPassing, checked 1 h ago

Build the EIP-3009 transferWithAuthorization typed data for a gasless USDC transfer on Base/Polygon/Arbitrum/Optimism/Ethereum/Monad/Celo/Avalanche/Sei - the exact EIP-712 object an agent signs with its OWN key to authorize an x402 payment. We construct it; we never sign or send. Non-custodial.

POST
https://agent402.tools/api/transfer-authorization
Price
$0.003
per call in USDC
Uptime
100%
last 30 days
Response time
265 ms
441 ms slowest 5%
Last check
Passed
1 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 · Watch with other listings

How to call it

POST https://agent402.tools/api/transfer-authorization

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://agent402.tools/api/transfer-authorization
content-type: application/json

{
  "amount": 0.01,
  "from": "0x1111111111111111111111111111111111111111",
  "network": "base",
  "to": "0x2222222222222222222222222222222222222222"
}

Parameters

ParameterTypeRequiredDescription
amountnumberYesUSDC amount (e.g. 0.01)
fromstringYespayer address (the wallet that will sign)
networkstringNochain: base | polygon | arbitrum | optimism | ethereum | monad | celo | avalanche | sei | robinhood (default base)
tostringYesrecipient address
validForSecondsnumberNohow long the authorization is valid (default 3600)

Example response

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

{
  "network": "base",
  "typedData": {
    "domain": {
      "chainId": 8453,
      "name": "USD Coin",
      "verifyingContract": "0x833589f…",
      "version": "2"
    },
    "message": {},
    "primaryType": "TransferWithAuthorization"
  }
}

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://agent402.tools/api/transfer-authorization' \
  -H 'content-type: application/json' \
  --data-raw '{"amount":0.01,"from":"0x1111111111111111111111111111111111111111","network":"base","to":"0x2222222222222222222222222222222222222222"}'

# 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://agent402.tools/api/transfer-authorization' \
  -H 'content-type: application/json' \
  --data-raw '{"amount":0.01,"from":"0x1111111111111111111111111111111111111111","network":"base","to":"0x2222222222222222222222222222222222222222"}' \
  | 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%2Fagent402.tools%2Fapi%2Ftransfer-authorization&method=POST
const res = await pay("https://agent402.tools/api/transfer-authorization", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "amount": 0.01,
    "from": "0x1111111111111111111111111111111111111111",
    "network": "base",
    "to": "0x2222222222222222222222222222222222222222"
  }),
});
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://agent402.tools/api/transfer-authorization",
        json={
            "amount": 0.01,
            "from": "0x1111111111111111111111111111111111111111",
            "network": "base",
            "to": "0x2222222222222222222222222222222222222222",
        },
    )
    print(res.status_code, res.text)

Security scan

No findings

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Recent checks

WhenResultHTTPTimePrice
1 h agoPassed402265 ms$0.003
6 h agoPassed402201 ms$0.003
10 h agoPassed402264 ms$0.003
14 h agoPassed402362 ms$0.003
18 h agoPassed402261 ms$0.003
Show 10 older checks
22 h agoPassed402266 ms$0.003
27 h agoPassed402187 ms$0.003
31 h agoPassed402323 ms$0.003
35 h agoPassed402195 ms$0.003
39 h agoPassed402189 ms$0.003
43 h agoPassed402359 ms$0.003
47 h agoPassed402187 ms$0.003
2 days agoPassed402188 ms$0.003
2 days agoPassed402420 ms$0.003
2 days agoPassed402246 ms$0.003