System Design
Designing large systems for scale, reliability, and maintainability.
CurrentadvancedGuide only -- no course yet
Overview
System design is the practice of architecting software systems to meet requirements like scale, availability, and consistency -- covering load balancing, caching, database scaling, and trade-offs between them. It's both a real engineering skill and a common senior technical-interview format.
- What it is
- The practice of designing how a system's components fit together to meet scale, reliability, and performance requirements.
- Why it's used
- Real systems eventually outgrow a single server and a single database -- system design is the vocabulary for reasoning about what to do next.
- Where it fits
- After backend and database fundamentals; a common focus of mid-to-senior technical interviews.
Core concepts
- Load balancing
- Caching
- Database scaling (replication, sharding)
- Consistency vs. availability trade-offs
- Rate limiting
Example
System design is less about one 'correct' architecture and more about explicitly naming the trade-off you're making and why it fits the requirements.
// A classic trade-off:
// Cache reads aggressively for speed,
// but now a write must invalidate (or accept stale) cached data.
// There is no free lunch -- every choice trades one property for another.Common use cases
- Architecting systems expected to scale
- Senior/staff technical interviews
Project ideas
- Design (on paper) how you'd scale a simple blog from 100 to 1 million daily readers, identifying each bottleneck in order