LN Markets Stream API

Realtime market data and private events over JSON-RPC 2.0 WebSocket

Version 1.0.0 — JSON-RPC 2.0 over a single persistent WebSocket. Use it to push trades, fund deposits, OHLC candles, and ticker updates to your client without polling.

Why Stream

• Push-based — receive market and account events the moment they happen.
• Single connection — multiplex public market data and private account events on one socket.
• JSON-RPC 2.0 — request/response, notifications, and errors follow a well-known spec.
• Permission-scoped — private topics honor the same scopes (account:*, futures:*) as the REST API.

At a glance

• Endpoint wss://stream.lnmarkets.com/v1
• Protocol WebSocket, JSON-RPC 2.0 messages
• Methods 8 (subscribe, unsubscribe, authenticate, …)
• Topics 12 (public market data + private account events)
• Auth API key + HMAC-SHA256 signature, identical to REST v3

Sections

• Connection — endpoint, limits, message envelope, heartbeat
• Authentication — sign your requests with an API key, secret, and passphrase
• Methods — full request/response reference for every JSON-RPC method
• Subscriptions — payload reference for every topic

Quick start

const ws = new WebSocket('wss://stream.lnmarkets.com/v1')

ws.addEventListener('open', () => {
  ws.send(JSON.stringify({
    jsonrpc: '2.0',
    id: 1,
    method: 'subscribe',
    params: { topics: ['futures/inverse/btc_usd/ticker'] },
  }))
})

ws.addEventListener('message', (event) => {
  const message = JSON.parse(event.data)
  if (message.method === 'subscription') {
    console.log(message.params.topic, message.params.data)
  }
})

Authenticated topics need an extra step — call authenticate before subscribe. See Authentication for the signing recipe.

Client libraries

• TypeScript / JavaScript — @ln-markets/sdk (npm)
• Python — lnmarkets_sdk