Free Arbitrum One RPC Endpoint
Chain ID 42161 · ETH · multi-region with automatic failover
Arbitrum One (Chain ID 42161) is Ethereum's leading optimistic rollup — full EVM equivalence and fast finality. NodeFlare serves Arbitrum RPC from nodes close to your users with automatic failover.
Public endpoint — no API key
HTTPS
https://rpc.nodeflare.app/arb/publicWSS
wss://rpc.nodeflare.app/arb/ws/publicNeed higher limits? Use a keyed endpoint https://rpc.nodeflare.app/arb/v1/{YOUR_KEY} — get a free key →
Connect to Arbitrum One
curl -s -X POST https://rpc.nodeflare.app/arb/public \
-H 'content-type: application/json' \
-d '{"jsonrpc":"2.0","id":1,"method":"eth_blockNumber","params":[]}'import { ethers } from "ethers";
const provider = new ethers.JsonRpcProvider(
"https://rpc.nodeflare.app/arb/public"
);
const block = await provider.getBlockNumber();import { createPublicClient, http } from "viem";
const client = createPublicClient({
transport: http("https://rpc.nodeflare.app/arb/public"),
});
const block = await client.getBlockNumber();from web3 import Web3
w3 = Web3(Web3.HTTPProvider(
"https://rpc.nodeflare.app/arb/public"
))
print(w3.eth.block_number)Add Arbitrum One to your wallet
Network details for MetaMask, Rabby, or any EVM wallet — Arbitrum One chain ID 42161 (0xa4b1).
| Network name | Arbitrum One |
| RPC URL | https://rpc.nodeflare.app/arb/public |
| Chain ID | 42161 |
| Currency symbol | ETH |
| Block explorer | https://arbiscan.io |
Built for Arbitrum One
Perps, DEXs, and capital-efficient DeFi on Arbitrum. Every request routes to the nearest healthy node, with automatic failover and no per-request throttling — the gaps public endpoints leave.
Low-latency Arbitrum One RPC — 5 regions, geo-routed
We run our own bare-metal Arbitrum One nodes in 5 regions across US-East, US-West, EU and Asia — not a reseller of Alchemy or Infura. Every request is geo-routed to the region you call from: the gateway reads the Cloudflare edge location and picks the nearest healthy node, with automatic failover. A trading bot in Singapore hits our Singapore Arbitrum One node, not one in the US — real round-trip time saved on your hot path.
Arbitrum One RPC — FAQ
What is Arbitrum One's chain ID?
Arbitrum One's chain ID is 42161 (hex 0xa4b1). Its native currency is ETH and its block explorer is arbiscan.io. You can connect with NodeFlare's free public RPC at https://rpc.nodeflare.app/arb/public — no API key required.
How do I add Arbitrum One to MetaMask?
In MetaMask, open the network menu → "Add a network" → "Add a network manually", then enter — Network name: Arbitrum One; New RPC URL: https://rpc.nodeflare.app/arb/public; Chain ID: 42161; Currency symbol: ETH; Block explorer URL: https://arbiscan.io. Save, then switch to Arbitrum One. The endpoint is free and needs no account.
What is the Arbitrum One RPC URL?
NodeFlare's public Arbitrum One RPC URL is https://rpc.nodeflare.app/arb/public over HTTPS and wss://rpc.nodeflare.app/arb/ws/public over WSS. No API key is required for the public endpoint.
Is the Arbitrum One RPC free?
Yes. The public Arbitrum One endpoint is free with no sign-up. A free API key unlocks higher rate limits, heavy methods, and a dedicated path — 2,000,000 compute units per month, no credit card.
What are the Arbitrum One RPC rate limits?
The public endpoint is limited to 2 requests/second per IP. A free key gives 10 requests/second; paid plans scale to 500 req/s. Every plan includes all 22 supported chains.
Is NodeFlare a good Arbitrum One RPC provider?
NodeFlare is an independent Arbitrum One RPC provider that runs its own nodes — not a reseller or aggregator of third-party backends. The public endpoint is free with no sign-up; a free API key adds higher rate limits, WebSocket, and heavy methods (eth_getLogs, trace_*, debug_*) — 2,000,000 compute units per month, no credit card.
Is there a dedicated Arbitrum One RPC node?
Yes. NodeFlare runs its own dedicated Arbitrum One node(s), and every request is routed to the nearest healthy node with automatic failover. A free or paid key gives you a dedicated endpoint path with your own rate limits and full access to archive methods like eth_getLogs and debug_traceTransaction.
Go deeper
- Full Arbitrum One API reference → — supported methods, WebSocket, regions
- Rate limits & compute-unit costs → — what each method costs against your quota
- Pay per request with x402 → — Arbitrum One calls in USDC from $0.001, no account:
POST /arb/x402 - RPC for trading bots → and indexers → — low-latency, eth_getLogs-heavy workloads
- Screen a Arbitrum One token for scams → — ownership, honeypot check, holder concentration → one risk score
- Onchain tools for AI agents → — token-safety, wallet intelligence and RPC over MCP / x402
Build on Arbitrum One with a free key
Higher limits, a dedicated path, and automatic failover — every chain included. No credit card.
Get your free API key →Arbitrum One RPC methods
Per-method docs for Arbitrum One — parameters, compute-unit cost, and copy-paste examples.