eth_chainId - Celo

Example code for the eth_chainId JSON-RPC method. Complete guide on how to use eth_chainId JSON-RPC in GetBlock Web3 documentation.

This method returns the chain ID of the Celo network. The chain ID is used to prevent replay attacks across different EVM networks. Celo Mainnet uses chain ID 42220, while the Alfajores Testnet uses 44787. This value is essential for transaction signing and network identification.

Parameters

None

Request Example

curl -X POST https://go.getblock.io/<ACCESS-TOKEN>/ \
-H "Content-Type: application/json" \
-d '{
  "jsonrpc": "2.0",
  "id": "getblock.io",
  "method": "eth_chainId",
  "params": []
}'

const axios = require('axios');

const url = 'https://go.getblock.io/<ACCESS-TOKEN>/';

const payload = {
  jsonrpc: '2.0',
  id: 'getblock.io',
  method: 'eth_chainId',
  params: []
};

axios.post(url, payload, {
  headers: { 'Content-Type': 'application/json' }
})
.then(response => console.log(response.data))
.catch(error => console.error(error));

import requests
import json

url = "https://go.getblock.io/<ACCESS-TOKEN>/"

payload = {
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "method": "eth_chainId",
    "params": []
}

response = requests.post(url, headers={"Content-Type": "application/json"}, json=payload)
print(response.json())

use reqwest::Client;
use serde_json::json;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let client = Client::new();
    
    let payload = json!({
        "jsonrpc": "2.0",
        "id": "getblock.io",
        "method": "eth_chainId",
        "params": []
    });

    let response = client
        .post("https://go.getblock.io/<ACCESS-TOKEN>/")
        .header("Content-Type", "application/json")
        .json(&payload)
        .send()
        .await?;

    let result: serde_json::Value = response.json().await?;
    println!("{:#?}", result);
    
    Ok(())
}

Response Example

{
  "jsonrpc": "2.0",
  "id": "getblock.io",
  "result": "0xa4ec"
}

Response Definition

Parameter

Type

Description

result

string

Chain ID in hex (0xa4ec = 42220 for Mainnet)

Use Cases

Verify connection to correct network
Include in transaction signing for replay protection
Validate RPC endpoint configuration
Network detection in multi-chain applications
Wallet network switching

Error Handling

Error Code

Description

-32603

Internal error - node processing issues

-32000

Server error - RPC endpoint unavailable

SDK Integration

const { ethers } = require('ethers');

const provider = new ethers.JsonRpcProvider('https://go.getblock.io/<ACCESS-TOKEN>/');

const network = await provider.getNetwork();
console.log(network.chainId); // 42220n for Mainnet

import { createPublicClient, http } from 'viem';
import { celo } from 'viem/chains';

const client = createPublicClient({
  chain: celo,
  transport: http('https://go.getblock.io/<ACCESS-TOKEN>/')
});

const chainId = await client.getChainId();
console.log(chainId); // 42220 for Mainnet

const { newKit } = require('@celo/contractkit');

const kit = newKit('https://go.getblock.io/<ACCESS-TOKEN>/');

const chainId = await kit.web3.eth.getChainId();
console.log(chainId); // 42220 for Mainnet

Previousweb3_sha3 - Celo Nexteth_feeHistory - Celo

Last updated 2 hours ago

Was this helpful?

hashtagParameters

hashtagRequest Example

hashtagResponse Example

hashtagResponse Definition

hashtagUse Cases

hashtagError Handling

hashtagSDK Integration