eth_chainId — Ethereum JSON-RPC

Status: Available

Returns the EIP-155 chain ID of the network the node is connected to, as a hex string.

POSThttps://triport.io/eth

Network: Ethereum
Scope: eth_read_rpc
Auth: x-token: $TRIPORT_API_KEY (or Authorization: Bearer)
Rate limit: free — 10 RPS sustained · up to 20 burst · basic — 20 RPS sustained · up to 40 burst · pro — 100 RPS sustained · up to 200 burst · business — 250 RPS sustained · up to 500 burst; Burst capacity

Endpoint and plans: Ethereum RPC endpoint. Chain check: expected Ethereum value and how to check it.

Request

cURLJavaScriptPython

curl https://triport.io/eth \
  -H "Authorization: Bearer $TRIPORT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "eth_chainId",
    "params": []
  }'

const res = await fetch("https://triport.io/eth", {
  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 data = await res.json();
console.log(data);

import os


import requests


resp = requests.post(
    "https://triport.io/eth",
    headers={
        "Authorization": f"Bearer {os.environ['TRIPORT_API_KEY']}",
        "Content-Type": "application/json",
    },
    json={
        "jsonrpc": "2.0",
        "id": 1,
        "method": "eth_chainId",
        "params": [],
    },
)
data = resp.json()
print(data)

Response

JSON

Example

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

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.

Parameters

This method takes no parameters.

——optional

Pass an empty array [] as params.

Response

Response fields

Field	Type	Description
`result`	string	EIP-155 chain ID as a hex-encoded quantity. `0x1` is Ethereum mainnet.

Errors

Code	Meaning	When it happens
`401`	`trial_expired`	The API key's trial period has ended; upgrade to a paid tier to continue.
`429`	`rate_limited`	You exceeded the requests-per-second limit for your tier. Back off and retry.

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

Examples

JavaScript (fetch)

JavaScript

const res = await fetch("https://triport.io/eth", {
  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

Notes

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.
Chain ID vs network ID: see eth_chainId vs net_version, and the RPC and blockchain glossary for related terms.