Contract and decimals
USDT on Arbitrum One lives at 0xfd086bc7cd5c481dcc9c85ebe478a1c0b69fcbb9 with 6 decimals.
Get a signed webhook when an Arbitrum One address sends or receives USDT, about 6 seconds after the transfer.
The contract Chainhook watches, how amounts are scaled, and how long USDT takes to reach your endpoint.
0xfd086bc7cd5c481dcc9c85ebe478a1c0b69fcbb9Arbitrum produces several blocks per second. Polling an RPC per address burns through rate limits, and log queries have to be paged without gaps. Chainhook scans each block once, waits 20 blocks, and pushes only your transfers.
Create a webhook with network: "arbitrum", type: "token" and the address you want to watch. The signing secret is returned once.
Every Arbitrum One block is scanned. A matching USDT transfer is held until it is 20 blocks deep, about 6 seconds.
A transfer.detected event arrives with an X-Webhook-Signature header. Failed attempts are retried automatically, up to 3 attempts in total, waiting 1 minute, then 5 minutes between attempts.
{
"network": "arbitrum",
"type": "token",
"direction": "in",
"address": "0x3cbd8c73836d596859eb97160d296da84ae93e33",
"webhook_url": "https://api.example.com/webhooks/chainhook"
}What your endpoint receives for an incoming USDT transfer on Arbitrum One. amount is already scaled by decimals; amount_raw is the on-chain integer.
POST /webhooks/chainhook HTTP/1.1 Host: api.example.com Content-Type: application/json User-Agent: chainhook/1.x X-Webhook-Id: 01a0fbfd-4fe4-7a3c-8f21-6b9d0e4c7a15 X-Webhook-Signature: 7a12d02673420517279805cf8188a1a62c6f69706161ba5cf0a8ec91ea66b8e3 { "id": "01a0fbfd-4fe4-7a3c-8f21-6b9d0e4c7a15", "event": "transfer.detected", "created_at": "2026-10-02T09:41:17Z", "webhook_id": "01a0fbf2-fadc-7c3e-9b1a-4d6f2e8a5c71", "data": { "network": "arbitrum", "direction": "in", "type": "token", "transaction_hash": "0x9f3c1a7e5b2d8046c1e9a3f7b5d2c8e0a4f6b1d9c3e7a5f2b8d0c6e4a1f9b3d7", "transfer_index": 5, "block_number": 516832749, "block_hash": "0x4d8a2f6c0e9b3d7a1f5c8e2b6d0a4f9c3e7b1d5a8f2c6e0b4d9a3f7c1e5b8d2a", "block_timestamp": "2026-10-02T09:41:05Z", "confirmations": 20, "from": "0x8a6d4f369607ca7153e33925a82da3b95b623151", "to": "0x3cbd8c73836d596859eb97160d296da84ae93e33", "currency": "USDT", "amount": "640", "amount_raw": "640000000", "decimals": 6, "contract_address": "0xfd086bc7cd5c481dcc9c85ebe478a1c0b69fcbb9" } }
X-Webhook-Signature is a hex HMAC-SHA256 of the raw body, keyed with your webhook's secret. Reject any request where it doesn't match.
import crypto from 'node:crypto'; import express from 'express'; const app = express(); app.post( '/webhooks/chainhook', express.raw({ type: 'application/json' }), (req, res) => { const signature = req.get('X-Webhook-Signature') ?? ''; const expected = crypto .createHmac('sha256', process.env.CHAINHOOK_SIGNING_SECRET) .update(req.body) .digest('hex'); const valid = signature.length === expected.length && crypto.timingSafeEqual(Buffer.from(signature), Buffer.from(expected)); if (!valid) { return res.sendStatus(401); } const event = JSON.parse(req.body); // Skip event.id if you've already processed it. res.sendStatus(200); }, );
USDT on Arbitrum One lives at 0xfd086bc7cd5c481dcc9c85ebe478a1c0b69fcbb9 with 6 decimals.
Arbitrum settles to Ethereum but costs senders a fraction of mainnet gas, which makes it a common choice for USDT payouts and deposits.
USDT sent on Arbitrum lands at the same 0x address as on Ethereum, but only a webhook with network: "arbitrum" reports it.
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0xfd086bc7cd5c481dcc9c85ebe478a1c0b69fcbb9, with 6 decimals.
20 blocks, about 6 seconds.
Create an account and start with 100 trial detections for 1 month.