eth_chainId - SEI

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

Returns the chain ID of the Sei network. The mainnet chain ID is 1329 (0x531) and testnet is 1328 (0x530).

Parameters

• None

Request

cURL

curl

curl --location 'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data '{
    "jsonrpc": "2.0",
    "method": "eth_chainId",
    "params": [],
    "id": "getblock.io"
}'

JavaScript (axios)

request.js

import axios from 'axios';

const url = 'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/';

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

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

Python (requests)

request.py

import requests
import json

url = "https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/"

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

headers = {
    'Content-Type': 'application/json'
}

response = requests.post(url, headers=headers, data=payload)
print(response.json())

Rust (reqwest)

main.rs

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

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let client = Client::new();
    
    let response = client
        .post("https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/")
        .header("Content-Type", "application/json")
        .json(&json!({
            "jsonrpc": "2.0",
            "method": "eth_chainId",
            "params": [],
            "id": "getblock.io"
        }))
        .send()
        .await?;
    
    let result: serde_json::Value = response.json().await?;
    println!("{:#?}", result);
    
    Ok(())
}

Response

response.json

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": "0x531"
}

Response Parameters

Field	Type	Description
result	string	The chain ID as a hexadecimal string

Use Case

The eth_chainId method is essential for:

• Blockchain developers building applications on Sei

• Wallet applications requiring network data

• Analytics platforms tracking Sei network activity

• DeFi protocols integrating with Sei's parallelized EVM

Error Handling

Common errors when using this method:

Error Code	Message	Description
-32700	Parse error	Invalid JSON
-32600	Invalid Request	JSON is not a valid request object
-32601	Method not found	Method does not exist
-32602	Invalid params	Invalid method parameters
-32603	Internal error	Internal JSON-RPC error
-32000	Invalid input	Generic input error
-32500	Cross-VM error	Error in cross-VM operation (Sei-specific)

Web3 Integration

t

Ethers.js

ethers.js

import { ethers } from 'ethers';

const provider = new ethers.JsonRpcProvider('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/');

// Using ethers provider methods
const result = await provider.send('eth_chainId', []);
console.log(result);

Viem

viem.js

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

const client = createPublicClient({
    chain: sei,
    transport: http('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/')
});

// Using viem's request method
const result = await client.request({
    method: 'eth_chainId',
    params: []
});
console.log(result);