Pick a module, any module
Core Concepts
Scalability, availability, CAP theorem, and the vocabulary everything else builds on.
9 lessonsNetworking Fundamentals
OSI model, DNS, HTTP, TCP vs UDP, and load balancing.
8 lessonsAPI Fundamentals
REST vs GraphQL, WebSockets, webhooks, idempotency, and rate limiting.
8 lessonsDatabase Fundamentals
ACID, indexes, sharding, replication, and SQL vs NoSQL.
9 lessonsCaching Fundamentals
Caching strategies, eviction policies, distributed caches, and CDNs.
5 lessonsAsynchronous Communication
Pub/sub, message queues, and change data capture.
3 lessonsDistributed Systems & Microservices
Heartbeats, consensus, distributed locks, circuit breakers, and tracing.
8 lessonsArchitectural Patterns
Client-server, microservices, serverless, event-driven, and peer-to-peer.
5 lessonsSystem Design Tradeoffs
Ten head-to-head decisions you’ll be asked to justify in interviews.
10 lessonsInterview Practice
A framework for any prompt, plus easy, medium, and hard practice problems.
18 lessonsBuilt to actually stick
A few things beyond plain text, built where they genuinely help.
Diagrams that show the mechanism
Core Concepts lessons pair their explanation with a branded, animated diagram of the actual flow — not a decorative box-and-arrow filler.
Progress that stays on your device
Mark lessons complete and pick up where you left off. Tracked in your browser only — nothing is ever sent anywhere.
Ready to stop dreading the interview?
Start with Core Concepts — everything else in the course builds on it.
Start Learning →