eth_chainId on zkSync Era
Everything below was measured on 2026-10-13 by calling eth_chainId on zkSync Era 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.
zkSync Era 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 zkSync Era 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 + value. balance: 0, fee: 1900500021000, value: 1"). Unprotected transactions are accepted at the RPC, so replay protection depends on your wallet signing with the chain ID.
| eth_chainId | 0x144 (324) |
|---|---|
| net_version | 324 |
Example request
curl -s https://rpc.swiftnodes.io/rpc/zksync?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 zkSync Era before signing
import { createPublicClient, http } from "viem";
const client = createPublicClient({
transport: http("https://rpc.swiftnodes.io/rpc/zksync?key=YOUR_API_KEY"),
});
const id = await client.getChainId(); // 324
if (id !== 324) throw new Error(`wrong chain: ${id}`);
// Add zkSync Era to a browser wallet
await window.ethereum.request({
method: "wallet_addEthereumChain",
params: [{
chainId: "0x144",
chainName: "zkSync Era",
nativeCurrency: { name: "ETH", symbol: "ETH", decimals: 18 },
rpcUrls: ["https://rpc.swiftnodes.io/rpc/zksync?key=YOUR_API_KEY"],
}],
});Other methods on zkSync Era
- eth_blockNumberSupported
- eth_getBalanceSupported
- eth_getBlockByNumberSupported
- eth_getTransactionByHashSupported
- eth_getTransactionReceiptSupported
- eth_callSupported
- eth_estimateGasNot measured
- eth_gasPriceSupported
- eth_maxPriorityFeePerGasSupported
- eth_sendRawTransactionSupported
- eth_getTransactionCountSupported
- eth_getCodeSupported
- eth_subscribeSupported
- eth_getLogsSupported
- eth_getBlockReceiptsSupported
- eth_feeHistorySupported
- eth_getProofNot available
- eth_createAccessListNot available
- 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
- 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
- Arbitrum Nova
- Immutable zkEVM
Frequently asked questions
Does zkSync Era support eth_chainId?
Yes. eth_chainId answered on the SwiftNodes zkSync Era endpoint when our weekly probe called it through the customer path (2026-10-13).
What is the zkSync Era chain ID?
324 in decimal, 0x144 in hex, as returned by eth_chainId on 2026-10-13.
How do I add zkSync Era to MetaMask?
Call wallet_addEthereumChain with chainId 0x144, the native currency ETH with 18 decimals, and your RPC URL; the example on this page has the full object.
zkSync Era endpoints, live block height and WebSocket status are on the zkSync Era RPC page.
One key covers every chain we serve, and SwiftNodes has a free tier.