The pedagogy

Built on learning science, not vibes.

You're not lazy and you're not bad at system design. The problem is that the materials out there ask you to read, skim, and hope it sticks. DesignGraph replaces all of that with calibrated practice. Here's exactly how it works.

The system

Four moving parts, working in tight feedback.

Every decision — what you see next, when a topic resurfaces, whether an answer counted — comes from these four components interacting.

STEP 01

A diagnostic calibrates where you are.

Your first session isn't a lecture — it's a short, adaptive diagnostic that probes the edges of your knowledge. Within ~30 minutes, the system has a live map of which sub-skills you've mastered, which are shaky, and which are blanks. That map becomes the starting state of your graph.

STEP 02

A knowledge graph models every concept and its prerequisites.

Caching depends on consistency. Sharding depends on hashing and replication. Quorum depends on failure models. We've mapped out every concept in a FAANG design round as a node, and every prerequisite as an edge. The graph is what lets us put you on the exact frontier of what you can learn next — never too easy, never impossible.

STEP 03

Each session is a sequence of calibrated drills.

No videos. No case studies to read. You open DesignGraph and you get 4–8 short drills — sometimes a numeric back-of-envelope, sometimes a written trade-off, sometimes a design sketch. Every drill targets a specific node on your frontier. The grader reads your answer with the strictness of a Staff engineer, then gives you precise feedback within seconds.

STEP 04

Spaced review keeps everything from fading.

Forgetting is not a character flaw — it's the default state of the human brain. The graph tracks when you last demonstrated a concept and schedules it back into your review queue right before it would decay. By interview day, every concept you've touched is still warm.

STEP 05

Explainers appear exactly when you need them.

When you get stuck on a drill, the system doesn't tell you to go watch a 30-minute video. It surfaces a short, focused explainer written for precisely your current misunderstanding — and then puts you right back in the driver's seat with a different drill on the same idea.

STEP 06

Your dashboard tells you the truth.

Not "streak = 14 days". Not "you've watched 74% of the course". Your dashboard shows, for every sub-skill on the graph: interview-ready, shaky, or not yet attempted. That's the only metric that matters when you're three weeks out from the onsite.

The graph

This is roughly what your graph looks like.

Lit-up nodes are concepts you've mastered. Glowing edges are prerequisites that unlocked something new. Dim nodes are what's coming. Every session re-shapes it.

See yours →
Learning principles

Five ideas we don't compromise on.

Principle 01

Practice beats exposure.

Reading about load balancing is not learning load balancing. Every minute you spend with DesignGraph is a minute you're actively producing an answer.

Principle 02

Specific beats general.

Generic "system design best practices" don't carry you through a real round. We break every topic down to concrete, testable sub-skills — and drill each one until it's automatic.

Principle 03

Feedback beats answer keys.

Bad feedback: "correct / incorrect". Good feedback: "your scheme works for reads but breaks under concurrent writes because you didn't serialize the update path." That's what our grader produces.

Principle 04

Calibration beats content.

A library of 10,000 problems doesn't help you if you can't pick which one to do today. The graph picks for you — so you spend your 30 minutes learning, not choosing.

Principle 05

Retention beats coverage.

Finishing every topic once is worse than finishing the core ones three times at the right intervals. We pick retention every time.

Principle 06

Honesty beats hype.

No "you're 87% ready!" dopamine-bait numbers. If your consistency story is shaky, the dashboard says so. That's the whole point — show up to the interview knowing what you know.

You've read enough. Open the graph.

30 minutes. No videos. You'll feel the difference by the end of session one.