Designing Real-Time Systems: How to Push Updates Without Polling

Ever built something that had to be real-time?
Live notifications, stock price dashboards, messaging apps, or even collaborative tools like Google Docs?

If your solution was something like, “let’s just poll the server every few seconds” — it’s time for an upgrade.

Polling is like asking your friend every 5 seconds if the food is ready.
Efficient? Nope. Annoying? Definitely.
There’s a better way: Push-based architectures.

Let’s explore how to design real-time systems that scale, feel snappy, and don't waste resources.

🧠 Why Polling Falls Short

Consumes bandwidth even when there’s no update
Latency-prone — users wait up to the next interval
Expensive at scale — imagine millions of clients asking the server the same question every few seconds

The internet has evolved — your systems should too.

🚀 Real-Time Alternatives That Just Work

Here’s how modern systems push updates to the client, instead of the client begging for them:

1. WebSockets

A full-duplex communication channel over a single TCP connection.

const socket = new WebSocket('ws://yourserver.com');
socket.onmessage = function(event) {
  console.log('Update received:', event.data);
};

Ideal for chat apps, live feeds, and dashboards
No re-connection unless network breaks
Low-latency magic 🧙

🔗 Deep dive on WebSocket protocol (MDN)

2. Server-Sent Events (SSE)

Perfect for sending one-way updates from server → client

const source = new EventSource('/events');
source.onmessage = function(event) {
  console.log('Event:', event.data);
};

Simpler than WebSockets
Built on HTTP (works great with proxies)
Best for news feeds, logs, and live scores

3. Firebase & Supabase

Want real-time without building the backend?
Use platforms with real-time DB triggers built in.

Firebase: Firestore’s .onSnapshot() gives real-time updates
Supabase: Listens to PostgreSQL changes via websockets

// Supabase example
supabase
  .channel('room1')
  .on('postgres_changes', { event: '*', schema: 'public', table: 'messages' }, payload => {
    console.log('Change received!', payload);
  })
  .subscribe();

🔗 Firebase Realtime Database Docs
🔗 Supabase Real-Time Guide

4. GraphQL Subscriptions

Love GraphQL? Subscriptions let you define a subscription type and get real-time updates pushed over WebSocket.

subscription {
  newMessage {
    id
    content
  }
}

Requires WebSocket backend setup
Tight integration with the rest of your GraphQL queries

🔗 Apollo GraphQL Subscriptions

✅ Choosing the Right One (No Table, Just Clarity)

WebSockets: You need fast, two-way comms (e.g. chat, multiplayer games)
SSE: You only need updates from server to client, and prefer HTTP
Firebase/Supabase: You want real-time without server-side complexity
GraphQL Subscriptions: You're deep into GraphQL and want structured real-time APIs

🧰 Pro Tips for Designing Real-Time Systems

Don’t forget authentication – securing WebSockets and SSE streams is essential
Use backpressure handling – avoid flooding clients with unnecessary updates
Keep payloads small – real-time ≠ dump-everything
Monitor connections – real-time = live visibility into failures too

🎯 Want to See Real-Time In Action?

Try building a quick real-time app using:

Socket.IO Chat App (GitHub)

Or just fork one of these open-source playgrounds and experiment 👨‍💻

💬 Have you worked with real-time systems before?
Which method did you use and why?
Drop your thoughts below — let’s discuss what works (and what breaks )

🔔 Follow [DCT Technology] for more tips, tricks & dev deep dives like this one.

#websockets #realtime #webdevelopment #supabase #graphql #firebase #javascript #systemdesign #devtools #programmingtips #frontenddevelopment #backenddevelopment #dcttechnology

DCT Technology Pvt. Ltd. @dct_technology