Why should you care?

Chat, live scores, and stock tickers need instant server → client messages.

See it live — copy this example

Paste into an HTML file or the browser console (F12). Use Run below when the live editor is available.

// WebSocket sketch (needs a ws:// server)
// const ws = new WebSocket("wss://example.com/live");
// ws.onmessage = (e) => console.log(JSON.parse(e.data));

Run Example »

Edit the code below and click Run to see the result in Toolliyo’s live editor.

What happened?

• WebSocket keeps a open connection both ways.
• SSE is one-way server push over HTTP.

Practice next

1. Sketch WebSocket onmessage handler.
2. Compare wasteful setInterval fetch polling.
3. Close socket on beforeunload.
4. Simulate messages with setInterval updating a live price div.
5. Add reconnect logic sketch with exponential backoff comments.

Remember

WebSocket = two-way SSE = server push Better than constant polling

ScriptVerse trading ticker

Trading dashboard opens WebSocket to stream bid/ask updates instead of polling REST every second.

Outcome: Real-time APIs cut latency and server load for live ScriptVerse analytics.