Arbitrum WebSocket RPC

Stream Arbitrum data in real time over a WebSocket connection — new blocks, pending transactions, and contract events — instead of polling. Every SwiftNodes plan includes a Arbitrum WebSocket endpoint alongside HTTP, with flat-rate pricing and no KYC.

Endpoint

wss://rpc.swiftnodes.io/ws/arbitrum?key=YOUR_API_KEY

The HTTP endpoint for Arbitrum is https://rpc.swiftnodes.io/rpc/arbitrum?key=YOUR_API_KEY. One API key works for both, and across all 75+ supported chains.

Subscribe to Arbitrum in real time

import { createPublicClient, webSocket } from "viem";

const client = createPublicClient({
  transport: webSocket("wss://rpc.swiftnodes.io/ws/arbitrum?key=YOUR_API_KEY"),
});

// Stream new Arbitrum blocks as they're produced (~~250 milliseconds apart)
const unwatch = client.watchBlocks({
  onBlock: (block) => console.log("new block", block.number),
});

What you can subscribe to

• New block headers (newHeads) — react the moment a block lands
• Pending transactions (newPendingTransactions) — watch the mempool
• Contract event logs (logs) — filter by address and topics

Arbitrum is an Optimistic Rollup (Arbitrum Nitro), with ~~250 milliseconds block times and soft: <1s. hard (l1): ~7 days (optimistic rollup challenge window) finality. That cadence sets how frequently new-block subscriptions fire.

Frequently asked questions

See the full Arbitrum RPC page for chain details, or the WebSocket docs for the complete method list.