Course · intermediatefree
System Design, from first principles
How real systems scale - and why every choice costs something.
Load balancers, caches, queues, databases that shard, and the trade-offs behind every choice. No memorized buzzwords: each lesson builds a system up from one box to planet-scale and shows what breaks at every step. Free while in early access.
4 modules12 lessons ~5h total
Start lesson 1: The single-box app What you'll be able to do
- Sketch a credible architecture for any product in an interview
- Know when you need a cache, a queue, or a replica - and when you don't
- Reason about failure: what breaks first, and what the blast radius is
- Read real engineering blogs and actually follow the decisions
Syllabus
Module 1
One server, and why it dies
- 01The single-box appEvery website starts as one computer. Learn the four parts inside it, and which one gives up first when a crowd shows up.20 min
- 02Vertical vs horizontal scalingYour shop is full. Do you build a BIGGER shop, or open MORE shops? Both work - and each one breaks in its own way.20 min
- 03Load balancersMeet the person standing at the street corner sending each customer to the right shop - and see what happens when a shop catches fire.25 min
Module 2
State: the hard part
- 04Databases under loadIndexes, connection pools, and the query that takes the site down. Reading an EXPLAIN like a story.25 min soon
- 05ReplicationRead replicas, replication lag, and the classic bug: the user who can't see their own write.20 min soon
- 06ShardingSplitting data across machines: shard keys, hot partitions, and why resharding is everyone's nightmare.25 min soon
- 07CachingCache-aside vs write-through, TTLs, invalidation, and the thundering herd that follows a cold cache.20 min soon
Module 3
Moving work off the request path
- 08Queues & async workWhy the slow thing should never block the user: producers, consumers, retries, and dead-letter queues.20 min soon
- 09Idempotency & exactly-once (the lie)At-least-once delivery is what you actually get - designing handlers that survive being called twice.20 min soon
Module 4
Putting it together
- 10Design: a URL shortenerThe interview classic, done honestly: estimation, data model, cache strategy, and the redirect hot path.30 min soon
- 11Design: a news feedFan-out on write vs read, celebrity problems, and pagination that doesn't fall over.30 min soon
- 12Design: a chat systemWebSockets at scale, presence, message ordering, and delivery guarantees users can feel.30 min soon
Start the course free
Create an account and the full syllabus opens in your dashboard - no card needed while the course is in early access.
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