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System design you can run.

Learn it in a free course. Build it on a canvas. Push simulated load and failures through it until something breaks, then defend every decision in an AI mock interview.

Start learning free
  • Free course, no card
  • Runs in your browser
  • High- and low-level design
  • 151free lessons in 7 tracks, each with recall questions
  • 71graded problems: 41 high-level, 30 low-level
  • 33component types that carry capacity, latency and cost
  • 45 minAI mock interviews, by voice or text

Where are you starting from?

Pick the one that fits. Same product, a different first hour.

One design, four steps.

The same design moves from the lesson to the canvas to the run to the interview, so every piece of feedback is about what you built.

Say it out loud before the real one.

A timed system design interview, spoken or typed, with an AI interviewer who asks about the design on your canvas and what its run showed.

  • 20, 30 or 45 minutes, from requirements and estimation to the deep dive and wrap-up.
  • Follow-ups come from your design: what saturated, what failed, what it cost.
  • A report scores 10 dimensions out of 5, quotes your answers as evidence and estimates your level, from SDE-1 to Staff.
  • Recording is optional and off by default.
Try a mock interview

On Pro, paid from prepaid credits.

System design mockHigh-level designSDE-231:12 left

Dev

AI interviewer · speaking

You · mic onDeep dive

Dev

Your checkout service writes to Postgres on every order. What happens at the sale peak?

You

The write path holds, but reads pile onto the primary. I would move order history to a replica and cache the catalogue.

Dev

Your run shows the replica lagging two seconds at peak. What does a customer see?

You

Speaking
71of 100

Sample reportLeaning hireLevel estimate SDE-2

Each score links to the quote, the canvas or the run it came from, with a study plan, a PDF and an annotated replay.

Requirements
4 of 5
Estimation
3 of 5
API design
4 of 5
Data modelling
3 of 5
High-level design
4 of 5
Deep dive
3 of 5
Scalability
4 of 5
Reliability
2 of 5
Trade-offs
4 of 5
Communication
4 of 5

Check your instinct. 3 questions from the course.

Every lesson asks questions like these, and a review queue brings back the ones you miss until they stick.

151 lessons, 7 tracks

Browse the course

Graded by what your design does.

71 problems with targets for latency, errors, failure and cost. Hidden tests run your design against them, so the grade comes from evidence, not keywords.

  • Tests, not a reference diagramFunctionality, scalability, reliability, performance and cost targets, run against your design.
  • Stuck? Ask for less than the answerA nudge first, then a hint, then the reveal with its reasoning and the rejected alternatives.
  • Low-level design and machine codingClasses graded on structure, SOLID, coupling and concurrency, and coding rounds in Java, Python or TypeScript.
  • HLDCheckout and payment ledgersMoney moves once, even when requests retry.
  • HLDChat and presenceFan-out, ordering and who is online.
  • HLDVideo deliveryEdges, storage and the cost of a cold cache.
  • HLDEvent streams and metersThroughput, backpressure and replay.
  • HLDMulti-tenant APIs and rate limitsFairness when one tenant spikes.
  • HLDRegional failoverWhat degrades when a zone goes away.
  • HLDGrounded AI answersRetrieval, caching and guardrails.
  • LLDParking lots to job schedulersEntities, interfaces and how they relate.
  • CODEMachine coding roundsLRU caches, pub-sub brokers, undo and redo.
  • DRILLDesign pattern drillsSpot a pattern, then compare two.
Free5 Easy problems with a free account; all 71 on Pro.See the problems
58of 100

Interview readinessSample

SDE 2 needs 65. 7 points to go: work on scalability and reliability.

Requirements & estimation
62
Architecture & data
60
Scalability
48
Focus
Reliability
44
Focus
Trade-offs & communication
57
Low-level design
71
Review queue
6 due today
Streak
9 days
This week
1,240 XP

Know when you are ready.

Every lesson, problem and mock adds to one readiness score, measured against the level you are aiming for.

  • Focus tags point at your weakest areas.
  • A review queue brings back what you are about to forget.
  • Streaks, a weekly challenge, discussions and an opt-in leaderboard.
  • A certificate for each track you finish; on Pro, with a code anyone can verify.

Watch it in action, one short video at a time.

Short tutorials, each one a recording of the product. Press one to play it right here.

Hiring engineers? Interview on a design that runs.

Structured system design interviews on the canvas candidates already practise on. Every interviewer judges the same evidence.

Opening with a small group of design partners first.

  • A canvas that runs

    Load and failures show what holds, in the interview itself.

  • Anchored scorecards

    Every interviewer scores the same dimensions, each tied to evidence.

  • A debrief after every round

    AI summarises and suggests follow-ups. People make the decision.

  • Candidate data, handled

    Recordings, transcripts and notes under DPDP-ready controls, kept only as long as you choose.

Plans

Start free. Go Pro when you are ready.

Learn the fundamentals and solve your first problems for free. Pro opens every problem, the Sandbox and the AI that reviews your designs and runs your mock interviews.

See full pricing
FAQ

Questions? We have answers.

Why learn system design when AI can write the code?
Because AI writes code, not decisions. It can generate a service, a schema or a cache in seconds, but someone still has to decide which services should exist, where the data lives, what fails first and what it all costs at scale, and then defend those choices. That judgement is what senior roles and interviews now test, and it is what ArchiDepth trains: you build the design, run it under load and explain the evidence.
Can companies use ArchiDepth to hire system design talent?
That is what ArchiDepth for hiring teams is for: structured system design interviews on the same canvas candidates practice on, where the design actually runs, with anchored scorecards and an AI debrief while people make the decision. It is opening with a small group of design partners first, so startups, mid-size companies and enterprises can ask to join with a short request form.
What is ArchiDepth and how does it work?
ArchiDepth is a system design learning and interview practice platform. You learn each building block in a free course, draw an architecture on a canvas, and run it: simulated traffic and failures report latency, saturation and monthly cost. On Pro, AI reviews and AI mock interviews are grounded in those runs.
How do I prepare for a system design interview?
Learn the fundamentals first (caching, replication, partitioning, queues), then practise full problems out loud against a clock. On ArchiDepth you take the free course, solve high-level and low-level design problems that are graded by what your design does under load, and rehearse with an AI system design mock interview.
Does ArchiDepth have AI mock interviews for system design?
Yes, on Pro. An AI interviewer runs a timed high-level design interview, spoken or typed, while you design on the canvas. Your report gives an overall score, a score for each dimension with quotes and simulation results as evidence, and a level estimate.
Can I practise low-level design and machine coding?
Yes. Low-level design (LLD) problems are graded by how your classes and interfaces are built, from parking lots to job schedulers, and problems with a machine coding round run your code in Java, Python or TypeScript. Design pattern drills train you to spot and compare patterns.
What is free, and what needs Pro?
The course is free, and with an account so are five Easy practice problems, which you design and run on the canvas. The Sandbox, every other practice problem and every AI feature (the coach and the lesson tutor, AI reviews, run explanations and AI mock interviews) are part of Pro.
Who is this platform for?
Software engineers preparing for system design interviews at big tech and product companies, students learning system design from scratch, senior engineers and architects sharpening their judgement, and hiring teams that want to interview on a design that runs.
How is this different from other system design resources?
Most system design resources are text, videos or a whiteboard, so nothing tells you whether a design would hold. On ArchiDepth the design runs: you see what saturates, what fails and what it costs, and practice problems are graded on that evidence rather than on matching a reference diagram.
Do I need prior system design experience?
No. The course starts with the fundamentals and builds up track by track, so beginners can start there, while experienced engineers can go straight to hard problems and mock interviews.
What kind of problems can I practice?
71 graded problems across high-level and low-level design: checkout and payment ledgers, live chat and presence, video delivery, event streams and meter pipelines, multi-tenant APIs, rate limits and regional failover, grounded AI answers, and class designs from parking lots to job schedulers.
Get started

AI writes the code. Decision still needs you.

Start with the free course, build your first system on the canvas, and see how it holds under load.

Start learning freeTry a practice problem