DEV Community

Sreekar Reddy
Sreekar Reddy

Posted on • Originally published at sreekarreddy.com

🔔 Event-Driven Explained Like You're 5

React when something happens

Day 50 of 149

👉 Full deep-dive with code examples


The Doorbell

You don't stand at the door waiting all day for visitors.

Instead:

  1. You do your thing
  2. Doorbell rings → You react!
  3. Go back to what you were doing

Event-driven architecture works the same way!


The Old Way vs Event-Driven

Old (Polling):

Every second: "Any orders? Any orders? Any orders?"
Enter fullscreen mode Exit fullscreen mode

Wasteful! Constantly checking.

Event-Driven:

*Order comes in* → 🔔 → Process order!
Enter fullscreen mode Exit fullscreen mode

Often works well when there's something to do.


How It Works

Event: "New order created!"
    ↓
Listeners react:
  - Inventory: "I'll update stock"
  - Email: "I'll send confirmation"
  - Analytics: "I'll log this"
Enter fullscreen mode Exit fullscreen mode

Each service reacts to events it cares about.


Benefits

  • 🔌 Loose coupling (services don't know about each other)
  • 📈 Scalable (add more listeners anytime)
  • ⚡ Real-time (react instantly)

In One Sentence

Event-driven systems react to things that happen instead of constantly checking if something happened.


🔗 Enjoying these? Follow for daily ELI5 explanations!

Making complex tech concepts simple, one day at a time.

Top comments (0)