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Arbitrum One ARB transfer notifications, delivered as webhooks

Get a signed webhook when a Arbitrum One address sends or receives Arbitrum (ARB). Chainhook waits 20 blocks, about 6 seconds, then posts the transfer to your endpoint.

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ARB on Arbitrum One at a glance

The contract Chainhook watches, how amounts are scaled, and how long ARB takes to reach your endpoint.

Token
Arbitrum (ARB)
Network
Arbitrum One
Contract
0x912ce59144191c1204e64559fe8253a0e49e6548
Decimals
18
Confirmations
20
Time to webhook
About 6 seconds

How ARB ERC-20 webhooks work

Arbitrum 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.

  1. Register the address

    Create a webhook with network: "arbitrum", type: "token" and the address you want to watch. The signing secret is returned once.

  2. Chainhook waits for confirmations

    Every Arbitrum One block is scanned. A matching ARB transfer is held until it is 20 blocks deep, about 6 seconds.

  3. Your endpoint gets a signed POST

    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.

POST /v1/webhooks

{
  "network": "arbitrum",
  "type": "token",
  "direction": "in",
  "address": "0x3c3facc56a38aab3314e6a46dc4f1c9f303b023e",
  "webhook_url": "https://api.example.com/webhooks/chainhook"
}

Sample webhook payload

What your endpoint receives for an incoming ARB transfer on Arbitrum One. amount is already scaled by decimals; amount_raw is the on-chain integer.

ARB on Arbitrum One

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": "0xa6cac641f1f73270e85b12d9822dbaedae5bbbdcce99c8541549962ba8578433",
    "transfer_index": 3,
    "block_number": 516832900,
    "block_hash": "0xa4dca6ae29ad729ecc9cd6aee4c40e0861f88b7ddb9ea78ada852def15474fe7",
    "block_timestamp": "2026-10-02T09:41:05Z",
    "confirmations": 20,
    "from": "0x70598e346eb9a0653f0319cbce139f5a03e00d98",
    "to": "0x3c3facc56a38aab3314e6a46dc4f1c9f303b023e",
    "currency": "ARB",
    "amount": "1000",
    "amount_raw": "1000000000000000000000",
    "decimals": 18,
    "contract_address": "0x912ce59144191c1204e64559fe8253a0e49e6548"
  }
}

Verify the signature

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);
  },
);

Crediting ARB deposits safely

Only this contract

Chainhook reports ARB transfers from 0x912ce59144191c1204e64559fe8253a0e49e6548 only. Tokens on Arbitrum One that copy the ARB name or symbol are ignored, so a spoofed deposit never reaches your endpoint.

18 decimals

ARB on Arbitrum One uses 18 decimals. Credit the amount string, or scale amount_raw by decimals; never parse amounts as floating-point numbers.

Payments, deposits or holdings

Use direction: "in" for incoming ARB, "out" for withdrawals, or "any" to follow every movement on the address.

Credit once per transfer

Delivery is at least once. Store the event id, or transaction_hash with transfer_index, and skip events you have already processed.

Pay per detection

Start with 100 trial detections for 1 month and pay only for what you use. Paid plans add detections, webhooks, and per-detection overage.

  • Pay as you go

    $0/month

    Card required, no monthly fee

    • 100 trial detections for 1 month
    • 3 active webhooks
    • $0.001 per detection after the trial
    • Decoded transfers, delivered once confirmed
    Start for free

  • Starter

    $9/month

    or $90/year billed yearly

    • 25,000 detections a month
    • 25 active webhooks
    • $0.0006 per extra detection
    • Decoded transfers, delivered once confirmed
    Subscribe
  • Recommended

    Growth

    $29/month

    or $290/year billed yearly

    • 100,000 detections a month
    • 100 active webhooks
    • $0.0003 per extra detection
    • Decoded transfers, delivered once confirmed
    Subscribe

  • Scale

    $99/month

    or $990/year billed yearly

    • 400,000 detections a month
    • 200 active webhooks
    • $0.0002 per extra detection
    • Decoded transfers, delivered once confirmed
    Subscribe

Enterprise

Custom limits for teams that need more than 400,000 detections a month or more than 200 active webhooks. Contact us and we'll set up a plan around your volume.

Contact support

Prices in USD, plus applicable tax. Billed monthly or yearly, and paid allowances reset monthly. Cancel any time and keep your plan until the period ends.

Compare plans and estimate your bill

ARB on Arbitrum One questions

Can't find your answer? Contact support.

What is the ARB contract address on Arbitrum One?

0x912ce59144191c1204e64559fe8253a0e49e6548, with 18 decimals.

How do I detect an incoming ARB transfer on Arbitrum One?

Create a webhook with network: "arbitrum", type: "token", direction: "in" and the receiving address. Each confirmed ARB transfer arrives as a transfer.detected event.

How long until a ARB transfer is reported?

About 6 seconds. Chainhook waits 20 blocks on Arbitrum One before it sends the event.

Does Chainhook need my private key?

No. Chainhook only reads public blockchain data. You register a public address and receive events about it.

Watch your first wallet

Create an account and start with 100 trial detections for 1 month.

Start for free