What is System Design?

Example: "Design a Food Delivery App (like Zomato or Swiggy)"

Let’s break it down using a simple, real-world app:
Imagine you want to build your own food delivery platform.

Step-by-Step: System Design Process

1. 🧠 Understand Requirements

Functional Requirements:

• Users can browse restaurants and menus

• Place an order

• Track delivery in real-time

• Payment gateway integration

Non-Functional Requirements:

• Fast performance

• High availability (no downtime)

• Scalable (handle many users)

2. 🗺️ High-Level Architecture

Client (Mobile/Web App)

↓

API Gateway (handles requests)

↓

Backend Services (Auth, Orders, Payments)

↓

Database + Caching Layer

↓

3rd-party services (Payment, Maps)

3. Component Breakdown

• Frontend (React, Flutter, etc.): For user interface

• API Gateway: Entry point that routes traffic to services

• Authentication Service: Login/signup using OTP, Google, etc.

• Order Service: Handles order creation, status updates

• Restaurant Service: Manages restaurant data, menus

• Delivery Service: Assigns delivery partners, tracking

• Payment Service: Integrates Razorpay, Stripe, etc.

4. 🛢️ Database Design (Simplified)

Tables:

• Users (user_id, name, address, phone)

• Restaurants (restaurant_id, name, location)

• MenuItems (item_id, restaurant_id, name, price)

• Orders (order_id, user_id, restaurant_id, total, status)

• OrderItems (order_id, item_id, quantity)

Use Relational DB (like PostgreSQL) for transactions.
Use Redis for fast caching (e.g., restaurant menu or trending items).

5. 🚀 Scalability

• Add Load Balancer (like Nginx or AWS ALB)

• Use CDN for images and static content

• Break services into Microservices for easier scaling

• Add Message Queues (RabbitMQ/Kafka) for async jobs (like sending order notifications)

6. Handling Failures

• Retry failed payment requests

• Show fallback messages if restaurant info fails to load

• Use Monitoring Tools (like Prometheus + Grafana)

Final Thoughts

System design is not about drawing big diagrams — it's about thinking clearly.
Even if you're building a small blog, thinking about performance, security, and user experience is part of system design.