ToolVet
78trust / 100

B20 Transfer Preflight

by B20 Transfer Preflight in Onchain & crypto

x402 APIPassing, checked 1 h ago

🆕 The per-transaction B20 rail check: pass token + from + to (+ optional executor) and get one GO/HOLD/STOP on whether this exact transfer clears NOW — sender policy resolved against the sender, receiver policy against the recipient, executor policy against the operator, plus live transfer-pause. Every other B20 tool is per-token due diligence bought once; this is the check an agent runs on every payment. No ERC-20 tool can see it.

GET
https://402.com.tr/api/x402/b20-transfer-preflight
Price
$0.04
per call in USDC
Uptime
100%
last 30 days
Response time
502 ms
644 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

GET https://402.com.tr/api/x402/b20-transfer-preflight

Each call costs $0.04 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.

GET https://402.com.tr/api/x402/b20-transfer-preflight?address=0xb20000000000000000000186a08e781c38059eec&from=0x973a31858f4d2125f48c880542da11a2796f12d6&to=0xFe21a68f21d556A3C4274a44c2Fb5410c50cDa1C

Parameters

ParameterTypeRequiredDescription
addressstringYesB20 token address
executorstringNoExecutor (optional — transferFrom operator)
fromstringYesSender address
tostringYesRecipient address

Example response

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

{
  "address": "0xb20000000000000000000186a08e781c38059eec",
  "decision": "GO",
  "executor": null,
  "from": "0x973a31858f4d2125f48c880542da11a2796f12d6",
  "isB20": true,
  "symbol": "NADT",
  "to": "0xFe21a68f21d556A3C4274a44c2Fb5410c50cDa1C",
  "variant": "stablecoin"
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.04.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://402.com.tr/api/x402/b20-transfer-preflight?address=0xb20000000000000000000186a08e781c38059eec&from=0x973a31858f4d2125f48c880542da11a2796f12d6&to=0xFe21a68f21d556A3C4274a44c2Fb5410c50cDa1C'

# 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 - 'https://402.com.tr/api/x402/b20-transfer-preflight?address=0xb20000000000000000000186a08e781c38059eec&from=0x973a31858f4d2125f48c880542da11a2796f12d6&to=0xFe21a68f21d556A3C4274a44c2Fb5410c50cDa1C' \
  | 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 $0.04 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.04" });
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 $0.04 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2F402.com.tr%2Fapi%2Fx402%2Fb20-transfer-preflight
const res = await pay("https://402.com.tr/api/x402/b20-transfer-preflight?address=0xb20000000000000000000186a08e781c38059eec&from=0x973a31858f4d2125f48c880542da11a2796f12d6&to=0xFe21a68f21d556A3C4274a44c2Fb5410c50cDa1C");
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 $0.04 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.04"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://402.com.tr/api/x402/b20-transfer-preflight?address=0xb20000000000000000000186a08e781c38059eec&from=0x973a31858f4d2125f48c880542da11a2796f12d6&to=0xFe21a68f21d556A3C4274a44c2Fb5410c50cDa1C")
    print(res.status_code, res.text)

Security scan

No findings

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Recent checks

WhenResultHTTPTimePrice
1 h agoPassed402631 ms$0.04
6 h agoPassed402666 ms$0.04
10 h agoPassed402495 ms$0.04
15 h agoPassed402572 ms$0.04
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Show 10 older checks
23 h agoPassed402546 ms$0.04
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36 h agoPassed402505 ms$0.04
40 h agoPassed402586 ms$0.04
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2 days agoPassed402364 ms$0.04
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3 days agoPassed402434 ms$0.04