Lab 8

Event-Driven

Synchronous vs Asynchronous

Place an order. Sync makes the user wait through a 4-second chain. Async confirms in 200ms and drains work in the background.

Runs both models side by side.

Synchronous (blocking)

user waits for all

User waiting

0.0s

staring at a spinner…

💾 Save order200ms

✉️ Send Email1200ms

📱 Send SMS1000ms

🧩 Update CRM800ms

📈 Update Analytics800ms

Asynchronous (event-driven)

user freed instantly

User waiting

0.2s

Background queue

💾 Save order200ms

✉️ Send Email1200ms

📱 Send SMS1000ms

🧩 Update CRM800ms

📈 Update Analytics800ms

What just happened

▹Synchronous: the user waits through every side-effect in series — email, SMS, CRM, analytics — before 'Order confirmed'.
▹Asynchronous: the order is saved and confirmed in 200ms; side-effects are queued and drained in the background.
▹Same total work. The async user is free ~20× sooner — and a slow email can never delay an order.