Learn system design fundamentals

Overview

System design is the difference between a senior+ engineer and a strong mid-level one. Most people pick it up by osmosis, half-remembered diagrams, second-hand interview prep, and a vague sense that 'caches are good'. This course replaces all of that with a real mental toolkit you can defend out loud, applied to systems you actually use every day.

What you'll learn

By the end, you'll be able to do these, not just have read about them.

• 01

  Think in load balancers, caches, queues, and databases as primitives

• 02

  Estimate throughput, latency, and storage on a napkin

• 03

  Reason through trade-offs out loud without getting paralyzed

• 04

  Build a mental library of designs you can adapt to new problems

Suggested chapters

This is the typical chapter list. Your version is generated against your background and adapts as you go. It may compress, expand, or reorder these.

1. 01

   How to read a system

   Reading existing architectures the way an architect does, load, latency, failure modes, money.

2. 02

   Storage primitives

   Relational vs document vs key-value vs columnar, the trade space, not the trivia.

3. 03

   Caching, properly

   CDN, app-level, database, where each lives, what it costs, and how it goes wrong.

4. 04

   Queues & async work

   When sync breaks down, what queues actually buy you, and how to design idempotent consumers.

5. 05

   Load balancing & sharding

   Horizontal scaling without hand-waving, keys, hashing, hotspots, rebalancing.

6. 06

   Consistency & replication

   CAP without the dorm-room debate. Real reads-your-writes vs eventual decisions.

7. 07

   Designing for failure

   Timeouts, retries, circuit breakers, graceful degradation, what makes systems boring.

8. 08

   Capstone: design a real system

   End-to-end design of a system close to your actual work, defended out loud.

Common questions

• Will this prep me for FAANG-style design interviews?

  Yes. The chapters map directly to what gets asked. Pair it with System Design Interview Prep for cohort-style mock answers.

• Is this language-specific?

  No. The thinking is language-agnostic. Examples lean on whichever stack you tell Octo you actually use.

• Is this a fixed course, or is it built for me?

  Built for you. The chapter list below is a typical outline. Your actual course is generated against your role, experience, and what you already know, then adapts as you go.

• How long does it take?

  Most learners finish in 2–6 weeks at a normal pace, depending on the topic. Octo compresses where you're strong and slows down where you're weak.

• Is there a fixed schedule or cohort?

  No. You start when you start. There's no live session, no calendar, no deadline.

• Can I ask questions while I'm learning?

  Yes, every module has an AI Sidekick in the margin. Ask for a different example, push back, or get a clarifying analogy without leaving the page.

• What do I get at the end?

  A verifiable, HMAC-signed certificate with a public verify page. It records the modules passed, scores, and capstone, not just attendance.

• How much does it cost?

  Octo is in research preview, courses are open. We'll be transparent before pricing changes.