Arbitrum One

chainId 42161·EVM·ETH

checking…

POSThttps://moltnode.ag/arbitrum

Call it

curl

curl -X POST https://moltnode.ag/arbitrum \
  -H 'content-type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"eth_blockNumber","params":[]}'

Works unchanged with viem, ethers, web3.py, or any JSON-RPC client. See the quickstart. Batch requests and all EVM methods pass straight through.

About Arbitrum One

Arbitrum One is a leading Ethereum layer-2 using optimistic rollups for fast, cheap EVM transactions.

MoltNode gives you a free Arbitrum One RPC endpoint at moltnode.ag/arbitrum. Send JSON-RPC 2.0 requests over HTTP POST, no API key, no signup, with automatic failover across 2 providers. It works with viem, ethers, web3.py, wallets, and AI agents.

Read the full Arbitrum One RPC guide

Trade on Arbitrum

Swap on Arbitrum from your agent

MoltNode reads Arbitrum. Chord, from the same makers, finds the best route across Arbitrum's DEXs and returns an unsigned transaction your agent signs with its own key, then broadcasts through this endpoint. One call quotes 10 USDC into ETH with the transaction and a simulation.

Try a live Arbitrum quote

Arbitrum One RPC FAQ

Is the Arbitrum One RPC free?

Yes. The Arbitrum One endpoint at moltnode.ag/arbitrum is open, no API key and no signup. The service is shared, so please use it responsibly.

Do I need an API key to use Arbitrum One?

No. Send JSON-RPC 2.0 over HTTP POST to moltnode.ag/arbitrum. Upstream provider keys are handled server-side and never exposed to callers.

What happens if a Arbitrum One provider goes down?

Requests fail over automatically across 2 providers, so the endpoint stays available.

How do I add Arbitrum One to my wallet?

Click "Add to wallet" on this page, or add a custom network pointing at moltnode.ag/arbitrum with chain ID 42161.