Blast WebSocket RPC

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

Endpoint

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

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

Subscribe to Blast in real time

import { createPublicClient, webSocket } from "viem";

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

// Stream new Blast blocks as they're produced (~~2 seconds apart)
const unwatch = client.watchBlocks({
  onBlock: (block) => console.log("new block", block.number),
});

What you can subscribe to

• New block headers (newHeads): the subscription our health checks open on this chain
• Contract event logs (logs): filter by address and topics
• Pending transactions (newPendingTransactions), where the chain exposes a public mempool

Free keys get one WebSocket connection with new-block subscriptions only. Every other subscription listed here needs a paid plan, which also raises the connection limit.

Blast is an Optimistic Rollup (with native yield), with ~~2 seconds block times and soft: ~2s. hard (l1): ~14 days (extended optimistic challenge window) finality. That cadence sets how frequently new-block subscriptions fire.

Frequently asked questions

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