System Design

Design Systems
That Scale Reliably

Master the architecture patterns behind every senior engineering interview — CAP theorem, load balancing, caching, message queues, microservices, and distributed system design across 23 deep-dive topics.

Core Concepts ↓ Framework Guides →

Beginner → advanced

Interview-ready

Free forever

23TopicsCaching · LB · CAP · Kafka

200+ Interview Qs FAANG-level prep

60+ExamplesRunnable code

~4hRead TimeAll three guides

$0CostFree forever

Core System Design Topics

Start with fundamentals, then go deep on the patterns that appear in every senior interview — caching, load balancing, queues, and microservices.

Recommended Learning Path

New to backend? Follow this sequence. Each step builds on the previous one.

Step 01

Python Fundamentals

Functions, classes, decorators, virtual environments, pip. These are the building blocks everything else depends on.

Python Guide →

Step 02

Start with Flask

Learn routing, templates, and request handling without magic. Flask forces you to understand every layer.

Flask Guide →

Step 03

Level Up with Django

ORM, admin panel, auth system — the full-featured framework for building production applications fast.

Django Guide →

Step 04

APIs with FastAPI

Async, type-safe, auto-documented APIs. The modern choice for microservices and ML model serving.

FastAPI Guide →

Python Backend Frameworks

What is Backend Development?

Backend development is everything that happens behind the scenes of a web application — the server, the database, the business logic, and the APIs that power what users see on screen. While the frontend handles presentation, the backend handles data, security, and processing.

Web Servers

Handle HTTP requests and responses. Nginx, Gunicorn, or framework-built dev servers receive and route traffic.

Databases

Persist and query data. SQL databases like PostgreSQL for structured data, Redis for caching.

REST APIs

JSON endpoints that frontend, mobile, and third-party apps consume. The backbone of modern web architecture.

Authentication

User sessions, JWT tokens, and OAuth flows — controlling who can access what in your application.

Business Logic

The rules and workflows that define how your application behaves — validation, calculations, automation.

Deployment

Shipping to production with Docker, cloud platforms (Railway, Render, AWS), CI/CD pipelines.

Moderate

Django

The "batteries-included" framework

Full-stack framework with ORM, admin panel, auth, forms, and templates built in. Define your model once — Django generates the schema, admin UI, and forms for you.

from django.db import models
class Product(models.Model):
    name  = models.CharField(max_length=200)
    price = models.DecimalField(10, 2)
# → auto schema + admin UI

Full-Stack ORM Admin UI Auth

Best For SaaS, CMS, E-commerce

The lightweight microframework

Minimal core, maximum flexibility. You choose your ORM, auth library, and tools. Flask stays out of your way — perfect for learning fundamentals or building lean microservices.

from flask import Flask, jsonify
app = Flask(__name__)

@app.route('/api/hello')
def hello():
    return jsonify(msg='Hello!')

Microframework Lightweight Flexible Blueprints

Best For Prototypes, Microservices

Modern async API framework

Type hints + Pydantic + async = automatic validation, serialization, and OpenAPI/Swagger docs out of the box. One of the fastest Python frameworks available — built for APIs and ML model serving.

from fastapi import FastAPI
app = FastAPI()

@app.get('/items/{id}')
async def get_item(id: int):
    return {'id': id} # auto docs ✓

Async Type Hints Auto Docs Pydantic

Best For APIs, ML Serving

Read Time ~80 min

Open Guide →

Framework Comparison

Not sure which to pick? Here's a side-by-side breakdown across the dimensions that matter most.

	Django	Flask	FastAPI
Type	Full-stack framework	Microframework	API framework
Learning Curve	Moderate	Gentle	Steeper (async, types)
Performance	Good	Good	Excellent (async)
Built-in ORM	Yes (powerful)	No (use SQLAlchemy)	No (use SQLAlchemy)
Admin Panel	Auto-generated	Manual / Flask-Admin	None built-in
API Docs	DRF / drf-spectacular	Flask-RESTX / Flasgger	Auto (Swagger UI)
Async Support	Partial (Django 3.1+)	Partial (Flask 2.0+)	Native (ASGI)
Best For	SaaS, CMS, E-commerce	Prototypes, Microservices	APIs, ML serving, Speed
Used By	Instagram, Pinterest	Netflix, LinkedIn	Microsoft, Uber