An original, animated course on system design. From your first load balancer to acing the interview — every concept illustrated, every trade-off explained, zero jargon walls.
Twelve carefully sequenced topics. Start at the top, or jump to what you need — your progress is saved automatically.
Vertical vs horizontal scaling, latency vs throughput, the "nines" of availability, and back-of-envelope math.
Consistency, Availability, Partition tolerance — why you can only pick two, and what PACELC adds to the story.
Weak, eventual, and strong consistency. Failover and replication. Why two 99.9% services in series give you 99.8%.
How the internet's phone book works step by step, and how CDNs move bytes closer to your users.
L4 vs L7, algorithms, health checks, sticky sessions, and the subtle difference between an LB and a reverse proxy.
Cache-aside, write-through, write-behind, eviction policies, Redis data structures, and the three classic cache disasters.
ACID vs BASE, replication, federation, sharding, denormalization, four NoSQL families, and how to choose.
Message queues, delivery guarantees, Kafka's streaming model, task queues, and surviving back pressure.
HTTP/1.1 through HTTP/3, TCP vs UDP, REST vs gRPC, WebSockets vs SSE vs long polling.
Monolith vs microservices, service discovery, API gateways, circuit breakers, service meshes, sagas.
TLS, password hashing, sessions vs JWTs, OAuth 2.0, rate limiting, OWASP Top 10, and securing your APIs.
A five-step framework plus three fully worked examples: a URL shortener, the Twitter timeline, and a rate limiter.
Most system design resources are either too theoretical or too shallow. This course goes deep on every concept with animated diagrams, real company examples, and interview-ready explanations — all in plain HTML with zero dependencies.
"Distributed systems are just friendships
with extra failure modes." — Archie