Guide

Arbitrum One chain ID and RPC URL

Arbitrum One mainnet uses chain ID 42161 / 0xa4b1, RPC URL https://arb1.arbitrum.io/rpc, explorer https://arbiscan.io, and ETH as the gas token.

Answer first

Arbitrum chain ID quick answer

Use 42161 / 0xa4b1 for Arbitrum One mainnet, with RPC URL https://arb1.arbitrum.io/rpc, explorer https://arbiscan.io, and ETH as the gas token. The canonical indexed page for this chain is /status/arbitrum-one/.

Copy Arbitrum One config RPC and explorer Official docs and sources ETH gas token

Network Arbitrum One

Chain ID 42161 / 0xa4b1

RPC URL https://arb1.arbitrum.io/rpc

Explorer https://arbiscan.io

Gas token ETH

Checked April 30, 2026

Arbitrum One mainnet settings

RPC URL: https://arb1.arbitrum.io/rpc
Explorer: https://arbiscan.io
Chain ID: 42161
Chain ID hex: 0xa4b1
Currency symbol: ETH
Source docs: Arbitrum docs

Arbitrum One EIP-3085 config JSON

Text-only wallet_addEthereumChain parameters generated from reviewed fields. Main.net does not connect wallets or request permissions.

Copy-ready JSON

Review source documentation before using this in an app or wallet flow.

{
  "chainId": "0xa4b1",
  "chainName": "Arbitrum One",
  "nativeCurrency": {
    "name": "ETH",
    "symbol": "ETH",
    "decimals": 18
  },
  "rpcUrls": [
    "https://arb1.arbitrum.io/rpc"
  ],
  "blockExplorerUrls": [
    "https://arbiscan.io"
  ]
}

Official docs and source links

Main.net links to source documentation for verification. It does not rank RPC providers or make uptime, latency, privacy, or production reliability claims about public endpoints.

Arbitrum RPC endpoints

Setup caution

Compare bridge routes, withdrawal timing, and finality assumptions before moving large balances across rollups.

Always verify important details in official documentation before configuring software that may sign transactions. Use the status page copy path for the current reviewed config: /status/arbitrum-one/#copy-ready-config.