If you’ve ever tried to build a “live” feature like a chat app, notifications, stock price updates, IPL score updates, you’ve probably wondered:

Which one should I use? WebSockets? SSE? Polling? Or just cry?”

Don’t worry. Let’s make this simple, relatable, and fun.

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1. Polling - “Are we there yet?”

Imagine a kid on a road trip asking every 5 seconds:
“Are we there yet?”

That’s polling.

Your frontend keeps sending requests like:
“Hey server, any updates?”
“No.”
“Hey server, any updates now?”
“No.”
“Now?”
And so on… until the server finally says yes.

👍 Pros

• Simple to implement
• Works everywhere
• No special protocols needed

👎 Cons

• Wastes bandwidth (like asking for biryani every 10 seconds even though the cooker isn’t even on)
• Delayed updates depending on the polling interval
• Not scalable for millions of clients

🧠 When to use

• Small apps
• Infrequent updates
• When “good enough” is okay

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2. Server-Sent Events (SSE) - One-way radio from the server

Imagine the server as an RJ who broadcasts updates, and the client just listens.
You don’t talk back - it's like every school lecture ever.

SSE uses a simple HTTP connection where the server can push data whenever something changes.

👍 Pros

• Super lightweight
• Auto-reconnect built-in
• Great for real-time notifications and dashboards
• Simpler than WebSockets

👎 Cons

• One-way communication (server → client only)
• Doesn’t work in old browsers
• Doesn’t support binary data

🧠 When to use

• Live scores
• News feed
• Analytics dashboards
• Notifications

If your app doesn’t need the client to talk back continuously, SSE is a chill, low-maintenance option.

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3. WebSockets - Two-way communication… like a real relationship

WebSockets are like unlimited talk time packs.
Both client and server can talk whenever they want instantly.

Perfect for scenarios where you need real-time, bidirectional communication.

👍 Pros

• Fastest real-time experience
• Full duplex - both sides talk freely
• Ideal for chats, games, and live collaboration
• Efficient once the connection is established

👎 Cons

• Slightly more complex
• Needs special backend support
• Harder to scale when you have millions of users
• Requires load balancers that understand WebSocket upgrades

🧠 When to use

• Chat apps (WhatsApp vibes)
• Multiplayer games
• Trading apps (live price streaming)
• Collaborative tools (Google Docs-style editing)

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So… Which One Should You Choose?

Think of it like choosing a communication method among friends:

• Polling is like texting “Where are you?” every minute.
• SSE is like subscribing to your friend’s Instagram stories - you just watch updates as they come.
• WebSockets is like a phone call where both of you talk freely.

✔ If you need real-time + two-way chat-like communication → WebSockets

✔ If you need real-time but only one-way updates → SSE

✔ If you need simple periodic checks → Polling

Shoutout to this video where I first wrapped my head around WebSockets, SSE, and Polling. It explains the chaos beautifully and saved me hours of confusion: video