eth_chainId on Arbitrum Nova
Everything below was measured on 2026-10-13 by calling eth_chainId on Arbitrum Nova through the same endpoint customers use, and is re-measured weekly.
What eth_chainId does
Returns the chain ID (EIP-155) as a hex string. Wallets and libraries check it before signing, and the signature commits to it, so a transaction signed for one chain cannot be replayed on another.
Arbitrum Nova chain ID, as measured
net_version returns the same number as decimal text. Older tools read net_version; use eth_chainId, which is the value signatures commit to.
We sent Arbitrum Nova a legacy transaction signed without a chain ID (pre-EIP-155). Its nodes did not reject it for that: the answer was about the empty balance ("insufficient funds for gas * price + value: address 0x4c21270668899Cf33ebA67Dbb7d5A40E0Bbe3495 have 0 want 840000021001"). Unprotected transactions are accepted at the RPC, so replay protection depends on your wallet signing with the chain ID.
| eth_chainId | 0xa4ba (42,170) |
|---|---|
| net_version | 42170 |
Example request
curl -s https://rpc.swiftnodes.io/rpc/arbitrum-nova?key=YOUR_API_KEY \
-X POST -H "Content-Type: application/json" \
-d '{"jsonrpc":"2.0","id":1,"method":"eth_chainId","params":[]}'// Check you are on Arbitrum Nova before signing
import { createPublicClient, http } from "viem";
const client = createPublicClient({
transport: http("https://rpc.swiftnodes.io/rpc/arbitrum-nova?key=YOUR_API_KEY"),
});
const id = await client.getChainId(); // 42170
if (id !== 42170) throw new Error(`wrong chain: ${id}`);
// Add Arbitrum Nova to a browser wallet
await window.ethereum.request({
method: "wallet_addEthereumChain",
params: [{
chainId: "0xa4ba",
chainName: "Arbitrum Nova",
nativeCurrency: { name: "ETH", symbol: "ETH", decimals: 18 },
rpcUrls: ["https://rpc.swiftnodes.io/rpc/arbitrum-nova?key=YOUR_API_KEY"],
}],
});Other methods on Arbitrum Nova
- eth_blockNumberSupported
- eth_getBalanceSupported
- eth_getBlockByNumberSupported
- eth_getTransactionByHashSupported
- eth_getTransactionReceiptSupported
- eth_callSupported
- eth_estimateGasSupported
- eth_gasPriceSupported
- eth_maxPriorityFeePerGasSupported
- eth_sendRawTransactionSupported
- eth_getTransactionCountSupported
- eth_getCodeSupported
- eth_subscribeSupported
- eth_getLogsSupported
- eth_getBlockReceiptsSupported
- eth_feeHistorySupported
- eth_getProofSupported
- eth_createAccessListSupported
- debug_traceCallSupported
- trace_blockNot available
- trace_transactionNot available
eth_chainId on other chains
- Ethereum
- Base
- Arbitrum
- Optimism
- Polygon
- BNB Smart Chain
- Avalanche
- Sonic
- Linea
- Scroll
- zkSync Era
- Blast
- Mantle
- Gnosis
- Celo
- Berachain
- Monad
- Unichain
- Kaia
- PulseChain
- World Chain
- Ronin
- Abstract
- ApeChain
- MegaETH
- Fantom
- Lisk
- Hemi
- X Layer
- BOB
- Plasma
- Fraxtal
- Zora
- Story
- Soneium
- Sei
- Hyperliquid
- Taiko
- Morph
- Ink
- Katana
- Ethereum Classic
- opBNB
- Mode
- Flare
- Core
- Chiliz
- Telos EVM
- Tempo
- Cronos
- Manta Pacific
- Shibarium
- Boba Network
- Immutable zkEVM
Frequently asked questions
Does Arbitrum Nova support eth_chainId?
Yes. eth_chainId answered on the SwiftNodes Arbitrum Nova endpoint when our weekly probe called it through the customer path (2026-10-13).
What is the Arbitrum Nova chain ID?
42170 in decimal, 0xa4ba in hex, as returned by eth_chainId on 2026-10-13.
How do I add Arbitrum Nova to MetaMask?
Call wallet_addEthereumChain with chainId 0xa4ba, the native currency ETH with 18 decimals, and your RPC URL; the example on this page has the full object.
Arbitrum Nova endpoints, live block height and WebSocket status are on the Arbitrum Nova RPC page.
One key covers every chain we serve, and SwiftNodes has a free tier.