Learn system design — how to architect software at scale

Scalability, reliability, and trade-offs for real-world distributed systems

System design is the practice of architecting large-scale software systems: how do you design a service that handles millions of requests per second? How do you store and query petabytes of data? How do you ensure a system stays available when hardware fails?

These questions don't have single correct answers — system design is fundamentally about trade-offs. Consistency vs. availability. Latency vs. throughput. Cost vs. scalability. The skill is understanding the options, the trade-offs each choice entails, and how real systems (Twitter, Netflix, Uber, DoorDash) have solved these problems in practice.

System design is the subject most directly tested in senior engineering interviews — and it's the knowledge that distinguishes engineers who can build features from engineers who can build systems.

What you'll learn

Scalability Fundamentals

Vertical vs. horizontal scaling, stateless services, and the general principles that allow systems to grow.

Databases & Storage

SQL vs. NoSQL, sharding, replication, ACID vs. BASE, and how to choose the right storage system for each use case.

Caching

Cache patterns (cache-aside, write-through, write-behind), eviction policies, and distributed caches like Redis — how caching transforms system performance.

Load Balancing & Proxies

Distributing traffic across servers, health checks, sticky sessions, and the role of reverse proxies like Nginx.

Message Queues & Async Processing

Decoupling systems with queues (Kafka, RabbitMQ), event-driven architecture, and processing work asynchronously.

CAP Theorem & Consistency

Why distributed systems must choose between consistency and availability during network partitions, and what this means in practice.

APIs & Communication Patterns

REST vs. GraphQL vs. gRPC, rate limiting, authentication at scale, and service-to-service communication in microservices.

Why learn System Design?

System design interviews are required at every major tech company for senior engineering roles. Demonstrating system design fluency is what gets you from mid-level to senior, and from senior to staff. It's arguably the highest-leverage thing you can learn for career progression in software engineering.

Beyond interviews, system design knowledge makes you a more effective collaborator. When you understand database replication, caching strategies, and load balancing, you can contribute meaningfully to architectural discussions and make better decisions about the systems you work on every day.

Start learning System Design today

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