starknet_chainId - STRK

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

This method returns the chain ID of the network the node is connected to, encoded as a felt. Mainnet returns SN_MAIN (0x534e5f4d41494e), used for transaction signing and network guards.

Parameters

• None

Request

cURL

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

Axios

example.js

const axios = require('axios');

const response = await axios.post('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/', {
    jsonrpc: '2.0',
    method: 'starknet_chainId',
    params: [],
    id: 'getblock.io'
}, {
    headers: { 'Content-Type': 'application/json' }
});

console.log(response.data.result);

Request

example.py

import requests

response = requests.post(
    'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/',
    headers={'Content-Type': 'application/json'},
    json={
        'jsonrpc': '2.0',
        'method': 'starknet_chainId',
        'params': [],
        'id': 'getblock.io'
    }
)

print(response.json())

Rust

example.rs

use reqwest::Client;
use serde_json::{json, Value};

#[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": "starknet_chainId",
            "params": [],
            "id": "getblock.io"
        }))
        .send()
        .await?
        .json::<Value>()
        .await?;

    println!("Result: {}", response["result"]);
    Ok(())
}

Response

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": "0x534e5f4d41494e"
}

Response Parameters

Parameter	Type	Description
jsonrpc	string	JSON-RPC protocol version ("2.0")
id	string	Request identifier matching the request
result	string	Chain ID as a felt (SN_MAIN = 0x534e5f4d41494e)

Use Cases

• Transaction Signing: Include the chain ID in the transaction hash to prevent replay

• Network Guards: Reject transactions when the chain ID is unexpected

• Wallet Onboarding: Confirm a wallet is pointed at Starknet mainnet

• Multi-Network Config: Key configuration off the returned chain ID

Error Handling

Error	Message	Description
63 / UNEXPECTED_ERROR	Unexpected error	The node failed to return the chain ID
403 / RBAC: access denied	Access denied	The GetBlock access token is missing or incorrect