eth_chainId

eth_chainId returns the chain ID used for replay-protected transaction signing as introduced in EIP-155. The value is encoded as a hexadecimal string; for Ethereum mainnet this is 0x1 (decimal 1).

Use this method to confirm which network your RPC connection is pointed at before submitting transactions, and to derive the chain ID that must be included when signing EIP-155 transactions. It is the recommended way to detect the active network — prefer it over net_version, which returns the network ID as a decimal string and is not guaranteed to equal the chain ID.

This method takes no parameters and is available on every tier.

This method takes no parameters.

Response fields

Errors are returned in the standard JSON-RPC envelope. See the shared errors reference for the full error object shape and handling guidance.

JavaScript (fetch)

const res = await fetch("https://api.triport.io/v1/ethereum", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.TRIPORT_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    jsonrpc: "2.0",
    id: 1,
    method: "eth_chainId",
    params: [],
  }),
});


const { result } = await res.json();
console.log(result);                 // "0x1"
console.log(parseInt(result, 16));   // 1

TypeScript SDK (@triport/sdk)

import { Triport } from "@triport/sdk";


const client = new Triport({ apiKey: process.env.TRIPORT_API_KEY! });


const chainId = await client.ethereum.rpc<string>("eth_chainId", []);
console.log(chainId);                 // "0x1"
console.log(parseInt(chainId, 16));   // 1

Python (triport-sdk)

import os
from triport import Triport


client = Triport(api_key=os.environ["TRIPORT_API_KEY"])


chain_id = client.ethereum.rpc("eth_chainId", [])
print(chain_id)              # "0x1"
print(int(chain_id, 16))     # 1

• The result is a hex quantity — decode it with parseInt(result, 16) (JS) or int(result, 16) (Python) to get the integer chain ID.
• The chain ID is stable for the lifetime of a network and does not change between blocks, so the value is safe to cache for the duration of a session.
• Related: use net_version for the legacy decimal network ID, and eth_blockNumber to read the current head once you have confirmed the network.