System Design Basics
advancedTopic 12 of 12 in Backend Development
What it is
System design is the process of planning the architecture of a software system before building it — how data flows, where things are stored, how services communicate, and how the system handles growth.
Why backend developers need it
As applications grow, simple architectures break down. Understanding system design helps you make smart decisions about databases, caching, queues, and service boundaries before problems emerge.
What to learn
Monoliths vs. microservices
Load balancing and horizontal scaling
Caching strategies: Redis, CDN
Message queues: RabbitMQ, SQS
Database scaling: replication, sharding
API gateways and service mesh
Rate limiting and circuit breakers
Designing for failure and resilience
Practice project
Design Document
Write a system design document for a URL shortener: diagram the architecture, choose the database, plan the API, discuss how it would handle 10 million URLs, and outline caching and rate-limiting strategies.