NetworkId

Type-safe Ethereum network identifiers for peer-to-peer network discovery.

Overview

Branded number type representing Ethereum network IDs. Network IDs are used for peer-to-peer network identification and discovery, distinct from Chain IDs which are used for transaction replay protection.

NetworkId vs ChainId: These are different concepts!

NetworkId: Used for P2P network discovery (devp2p protocol)
ChainId: Used for transaction replay protection (EIP-155)

For most public networks they happen to be the same value, but they serve different purposes.

Quick Start

Basic Usage
Network Constants
RPC Usage

import * as NetworkId from '@tevm/voltaire/NetworkId'

// Create network ID
const mainnet = NetworkId.from(1)
const sepolia = NetworkId.from(11155111)

// Convert to number
NetworkId.toNumber(mainnet)  // 1
NetworkId.toNumber(sepolia)  // 11155111

// Compare network IDs
NetworkId.equals(mainnet, mainnet)  // true
NetworkId.equals(mainnet, sepolia)  // false

import { MAINNET, SEPOLIA, HOLESKY, GOERLI } from '@tevm/voltaire/NetworkId'

// Pre-defined network IDs
MAINNET   // 1
SEPOLIA   // 11155111
HOLESKY   // 17000
GOERLI    // 5 (deprecated)

import * as NetworkId from '@tevm/voltaire/NetworkId'

// Get network ID from node
async function getNetworkId(rpcUrl: string) {
  const response = await fetch(rpcUrl, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      jsonrpc: '2.0',
      method: 'net_version',
      params: [],
      id: 1
    })
  })
  const { result } = await response.json()
  return NetworkId.from(parseInt(result))
}

const networkId = await getNetworkId('https://eth.llamarpc.com')
console.log(NetworkId.toNumber(networkId))  // 1

Network Constants

Constant	Value	Network
`MAINNET`	1	Ethereum Mainnet
`SEPOLIA`	11155111	Sepolia Testnet
`HOLESKY`	17000	Holesky Testnet
`GOERLI`	5	Goerli Testnet (deprecated)

API Reference

Constructors

import * as NetworkId from '@tevm/voltaire/NetworkId'

// From number
const networkId = NetworkId.from(1)

// From pre-defined constant
import { MAINNET, SEPOLIA } from '@tevm/voltaire/NetworkId'

Methods

import * as NetworkId from '@tevm/voltaire/NetworkId'

const networkId = NetworkId.from(1)

// Convert to number
NetworkId.toNumber(networkId)  // 1

// Equality check
NetworkId.equals(networkId, NetworkId.from(1))  // true

NetworkId vs ChainId

Understanding the difference:

Aspect	NetworkId	ChainId
Purpose	P2P network discovery	Transaction replay protection
Protocol	devp2p	EIP-155
RPC Method	`net_version`	`eth_chainId`
Used In	Peer handshake	Transaction signing

For most public networks, NetworkId and ChainId have the same value:

import * as NetworkId from '@tevm/voltaire/NetworkId'
import * as Chain from '@tevm/voltaire/Chain'

// Mainnet: both are 1
const networkId = NetworkId.from(1)
const chainId = Chain.from(1)

// Sepolia: both are 11155111
const sepoliaNetworkId = NetworkId.from(11155111)
const sepoliaChainId = Chain.from(11155111)

However, private networks or some L2s may use different values for each.

Use Cases

Network Detection

import * as NetworkId from '@tevm/voltaire/NetworkId'
import { MAINNET, SEPOLIA, HOLESKY } from '@tevm/voltaire/NetworkId'

function getNetworkName(networkId: number): string {
  const id = NetworkId.from(networkId)

  if (NetworkId.equals(id, MAINNET)) return 'Ethereum Mainnet'
  if (NetworkId.equals(id, SEPOLIA)) return 'Sepolia Testnet'
  if (NetworkId.equals(id, HOLESKY)) return 'Holesky Testnet'

  return `Unknown Network (${NetworkId.toNumber(id)})`
}

Multi-Network Support

import * as NetworkId from '@tevm/voltaire/NetworkId'
import { MAINNET, SEPOLIA } from '@tevm/voltaire/NetworkId'

const RPC_URLS: Record<number, string> = {
  1: 'https://eth.llamarpc.com',
  11155111: 'https://rpc.sepolia.org'
}

function getRpcUrl(networkId: number): string {
  const url = RPC_URLS[networkId]
  if (!url) {
    throw new Error(`Unsupported network: ${networkId}`)
  }
  return url
}

Node Connection Validation

import * as NetworkId from '@tevm/voltaire/NetworkId'

async function validateNetwork(
  rpcUrl: string,
  expectedNetworkId: number
): Promise<boolean> {
  const response = await fetch(rpcUrl, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      jsonrpc: '2.0',
      method: 'net_version',
      params: [],
      id: 1
    })
  })
  const { result } = await response.json()
  const actualNetworkId = NetworkId.from(parseInt(result))
  const expected = NetworkId.from(expectedNetworkId)

  return NetworkId.equals(actualNetworkId, expected)
}

// Ensure connected to mainnet
const isMainnet = await validateNetwork('https://eth.llamarpc.com', 1)

Chain - Chain configuration with ChainId
PeerId - Peer identifiers for P2P
NodeInfo - Node information structure

References

EIP-155 - Chain ID for replay protection
devp2p Protocol - Ethereum P2P networking
JSON-RPC net_version - RPC method

Overview

Getting Started

Core Concepts

Skills

JSONRPCProvider

Contract

Primitives

Cryptography

EVM

Utils

Guides

Examples

Swift

Zig

Developer Documentation

Generated API (TypeDoc)

NetworkId

NetworkId

Overview

Quick Start

Network Constants

API Reference

Constructors

Methods

NetworkId vs ChainId

Use Cases

Network Detection

Multi-Network Support

Node Connection Validation

References

​NetworkId

​Overview

​Quick Start

​Network Constants

​API Reference

​Constructors

​Methods

​NetworkId vs ChainId

​Use Cases

​Network Detection

​Multi-Network Support

​Node Connection Validation

​Related

​References

NetworkId

Overview

Quick Start

Network Constants

API Reference

Constructors

Methods

NetworkId vs ChainId

Use Cases

Network Detection

Multi-Network Support

Node Connection Validation

Related

References