Celestia WebSocket RPC

Stream Celestia data in real time over a WebSocket connection instead of polling: new blocks and transactions through CometBFT event subscriptions. Every SwiftNodes plan includes a Celestia WebSocket endpoint alongside HTTP, with flat-rate pricing and no KYC.

Endpoint

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

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

Subscribe to Celestia in real time

// CometBFT event subscription (the same socket speaks the chain's native RPC, not eth_*)
const ws = new WebSocket("wss://rpc.swiftnodes.io/ws/celestia?key=YOUR_API_KEY");

ws.onopen = () => ws.send(JSON.stringify({
  jsonrpc: "2.0", id: 1, method: "subscribe",
  params: { query: "tm.event='NewBlock'" },
}));

// CometBFT delivers events with the subscribe request's id; the first frame is the acknowledgement.
ws.onmessage = (msg) => {
  const j = JSON.parse(msg.data);
  if (j.result?.data) console.log("new Celestia block", j.result.data.value.block.header.height);
};

What you can subscribe to

• New blocks (tm.event='NewBlock'): the subscription our checks open on this chain
• Transactions (tm.event='Tx'), narrowed with CometBFT event queries such as message.sender

Celestia is an Modular data availability layer (Cosmos SDK / CometBFT), with ~~6 seconds block times and single-block deterministic finality via cometbft once a block is committed (~6 seconds); light-node data availability confidence accrues through sampling. finality. That cadence sets how frequently new-block subscriptions fire.

Frequently asked questions

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