eth_chainId

Returns the chain ID used for transaction signing on zkSync Era.

Why zkSync? Build on Matter Labs' flagship zkEVM powering the Elastic Network of interoperable hyperchains with ZK Stack modular framework, hyperchain interoperability, native account abstraction, and $1.9B in tokenized real-world assets.

Use Cases

The eth_chainId method is essential for:

• Transaction signing - Ensure transactions are signed for the correct network
• Network verification - Confirm connection to the expected chain
• Multi-chain apps - Handle different networks programmatically
• Wallet integration - Validate network before transactions

Parameters

This method accepts no parameters.

Request

{
  "jsonrpc": "2.0",
  "method": "eth_chainId",
  "params": [],
  "id": 1
}

Returns

Type	Description
QUANTITY	Chain ID in hexadecimal

Response

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x1"
}

Code Examples

cURL

curl -X POST https://api-zksync-era-mainnet-full.n.dwellir.com/YOUR_API_KEY \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_chainId",
    "params": [],
    "id": 1
  }'

JavaScript

import { JsonRpcProvider } from 'ethers';

const provider = new JsonRpcProvider('https://api-zksync-era-mainnet-full.n.dwellir.com/YOUR_API_KEY');

const network = await provider.getNetwork();
console.log('Chain ID:', network.chainId);

// Verify network before transaction
async function verifyNetwork(expectedChainId) {
  const network = await provider.getNetwork();
  if (network.chainId !== BigInt(expectedChainId)) {
    throw new Error(`Wrong network. Expected ${expectedChainId}, got ${network.chainId}`);
  }
  return true;
}

Python

from web3 import Web3

w3 = Web3(Web3.HTTPProvider('https://api-zksync-era-mainnet-full.n.dwellir.com/YOUR_API_KEY'))

chain_id = w3.eth.chain_id
print(f'Chain ID: {chain_id}')

# Verify network
def verify_network(expected_chain_id):
    chain_id = w3.eth.chain_id
    if chain_id != expected_chain_id:
        raise ValueError(f'Wrong network. Expected {expected_chain_id}, got {chain_id}')
    return True

Go

package main

import (
    "context"
    "fmt"
    "log"

    "github.com/ethereum/go-ethereum/ethclient"
)

func main() {
    client, err := ethclient.Dial("https://api-zksync-era-mainnet-full.n.dwellir.com/YOUR_API_KEY")
    if err != nil {
        log.Fatal(err)
    }

    chainID, err := client.ChainID(context.Background())
    if err != nil {
        log.Fatal(err)
    }

    fmt.Printf("Chain ID: %d\n", chainID)
}

Related Methods

• net_version - Get network version
• eth_syncing - Check sync status