Interview prep · Data Structures · Algorithms · System Design
Crack the coding interview—see how every algorithm thinks.
Step through systems one move at a time. Watch the pointers, swaps, and decisions happen live—then prove you understood with exercises. Built for engineers targeting Amazon, Google, Meta, and 67 more companies.
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The problem
Reading about algorithms doesn't prepare you to write them.
01
Videos feel productive
You nod along, you finish the playlist — and then the same problem appears on a whiteboard and your mind goes blank.
02
Tutorials skip steps
"Obviously we use a hash map here." Nothing was obvious. The thinking between the lines is exactly what interviews test.
03
Random grinding wastes months
Solving random problems without a plan for YOUR target company means practicing hard instead of practicing right.
Understanding comes from watching the state change, step by step — and that is exactly what this platform does.
How it works
Three steps from confused to hired.
- 1
Watch it run
Every algorithm plays as a step-by-step animation of its variables and memory — comparisons, swaps, pointers, all live.
- 2
Prove you got it
Spaced-repetition flashcards, numeric drills, and coding challenges judged against hidden tests in your browser.
- 3
Study what your target company asks
70 company guides map their real hiring process and questions straight onto the exact lessons you should practice.
70
company interview guides
150
interactive step-by-step lessons
2401+
flashcards & practice questions
0
prior experience required
See it in action
This is what a lesson looks like.
Press play on any demo below. No signup, no setup — this is the actual product.
01Initialize bounds
low = 0, high = 10. The whole sorted array is the search space.
The invariant is that the target, if present, lives inside [low, high].
02Allocate the node
Create a new node with value 5.
A new node is just an object with a value and a next pointer.
Click a node to inspect it.
06Serve reads
Hot reads hit the cache first; the DB is queried only on a miss.
What's inside
Learn visually. Practice actively.
Step-trace everything
Arrays, linked lists, trees, graphs — every data structure plays like a movie of memory. You see what the code does, not just what it says.
Never forget what you learned
Flashcards with spaced repetition resurface weak topics right before you're about to forget them.
Code against hidden tests
Write solutions in the browser sandbox and get judged instantly — JavaScript or Python, no setup.
Draw system designs
Assemble architectures on an interactive canvas and check them against reference solutions.
Company guides
Your target company has a playbook. Study it.
Every guide covers the hiring process round by round, the questions they actually ask, and a study plan linking straight into the exact lessons you should practice.
- Amazon
- Microsoft
- Meta
- Apple
- Netflix
- NVIDIA
- Salesforce
- Oracle
- IBM
- Intel
- Adobe
- +58 more
FAQ
Questions people ask before buying.
I'm a complete beginner. Is this for me?
Yes — start with the Foundations track. It assumes zero knowledge and teaches Big-O notation, logarithms, recursion, and the other basics from scratch, in the same interactive format.
How is this different from LeetCode?
LeetCode gives you problems and lets you struggle. This platform teaches the underlying patterns visually first — watch the algorithm think — then gives you exercises and company-specific study plans so practice is targeted, not random.
What do I get with a paid plan?
All interactive lessons across Data Structures, Algorithms, and System Design, the Foundations track, and all 70+ company interview guides with question banks and study plans. A few lessons and two full company guides stay free forever so you can try before buying.
Monthly, Annual, or Lifetime - which should I pick?
Monthly (€29/mo) is flexible and cancels anytime. Annual (€79/yr) works out far cheaper if you're in it for the long haul. Lifetime (€99 once) never bills again and includes every future update. All plans unlock identical content.
How do cancellations work?
Cancel Monthly or Annual in one click from your account page - no emails, no calls. You keep full access until the end of the period you already paid for. Lifetime is a one-time purchase, so there is nothing to cancel or renew.
Pricing
Start free. Upgrade when you're ready to go all-in.
Free lessons and two full company guides forever. One plan unlocks everything else.
Monthly
Billed monthly · cancel anytime
- All interactive lessons & drills
- All company interview guides
- Progress dashboard with streaks and XP
- Cancel in one click - keep access until period end
Annual
Billed yearly · two months free vs monthly
- Everything in Monthly
- Priority access to new content drops
- Lock in today's rate before prices change
Lifetime
One payment · VAT included · keep forever
- Everything in Annual - forever
- Every future lesson and guide, at no extra cost
- Never billed again, ever
Secure checkout by Stripe Managed Payments - VAT included, card, Apple Pay & more. Subscriptions renew automatically until cancelled; cancel anytime from your account page.
Every topic, stepped through live. Start with the free traces.
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