Grind less.
Remember more.
You solved it once. Three weeks later — blank. crackpad fixes the part every other platform ignores: actually remembering the patterns.
Free forever tier — no card required.
Other platforms repackage the same problems. They change what you practice — crackpad changes how practice works.
Never forget
Spaced repetition (FSRS) schedules each pattern right before you'd forget it — so what you grind actually sticks.
Break memorization
The same pattern shows up as a different story every time. You learn the idea, not the wording.
Trustworthy judge
Deterministic validation across 9 languages — C#, Python, JS, TS, Go, C++, C, Java, Rust. No flaky verdicts.
How it works
Learn a pattern
Solve foundational problems with a real editor + instant judging.
It comes back
FSRS re-surfaces it — as a new story — right when memory fades.
Master, don't cram
Your weakness map shows exactly what to drill before the interview.
Everything you get
A complete interview-prep platform — memory science, a trustworthy judge, and every way to practice, all in one place.
Spaced repetition (FSRS)
Review only what's about to fade. Your memory schedule compounds — no daily cap, even on Free.
Story-varied problems
Every pattern retold as a fresh story, so you learn the idea — not a memorized wording.
9-language judge
C#, Python, JavaScript, TypeScript, Go, C++, C, Java and Rust — real sandboxed execution, per-language starters.
SQL problems
Multi-dialect SQL (SQLite & Postgres) with its own deterministic, dialect-neutral judge.
2,600+ problems
A deep catalog ordered foundations-first, from warm-ups to hard multi-step challenges.
Top 75 / 150 / 250
The most-asked interview problems, ranked by real company frequency — curated study lists.
Company question sets
Amazon, Google, Meta, Apple and Microsoft — practice the exact problems each one asks.
Mock interviews
Timed, no hints, no editorial. Ready-made company coding & SQL packs (2–4 questions) or roll your own.
Explore by topic
Jump straight into the most-used algorithms — Arrays, DP, Hashing, Graphs, Trees and more.
Curriculum & roadmap
Every pattern connected by prerequisites, foundations up — an interactive map of the whole path.
Weakness map & readiness
Progress tracking that shows exactly what to drill and how interview-ready you actually are.
Learning courses
Guided lessons with diagrams — like the System Design course — beyond raw problem grinding.
Plus notes per problem, progressive hints, saved code, community solutions, Google & GitHub sign-in, and dark mode.
Simple pricing
- Foundations, fully unlocked
- All 9 languages
- Spaced repetition — no cap
- Every layer — DP, graphs, trees…
- Mock interviews + saved code
- Full weakness analytics
Frequently asked questions
Is the free tier actually usable?
Yes — it's free forever, no card. You get the foundational layers fully unlocked, all 9 languages, a real editor with instant judging, and spaced repetition with no daily review cap. It's a small but complete experience, not a locked demo.
How is this different from LeetCode or Neetcode?
They change what you practice by repackaging problems. crackpad changes how practice works: spaced repetition so you don't forget, the same pattern shown as different stories so you can't memorize your way through, and a weakness map that tells you exactly what to drill.
Which languages can I solve in?
Nine: C#, Python, JavaScript, TypeScript, Go, C++, C, Java, and Rust — each with a real sandboxed judge and per-language starter code.
What is spaced repetition (FSRS)?
An algorithm that schedules each pattern to reappear right before you'd forget it. Instead of re-grinding everything, you review only what's about to fade — so prep time compounds instead of leaking.
Do you have SQL problems too?
Yes. There's a full SQL track with a dedicated multi-dialect judge (SQLite and Postgres), plus SQL-only mock interviews — so database-heavy roles are covered alongside coding.
Can I prep for a specific company?
Yes. Problems are tagged by company (Amazon, Google, Meta, Apple, Microsoft) and ranked by how often each is asked, and there are ready-made company mock interviews in 2–4 question coding and SQL packs.
Is there more than just problems?
Yes — curated Top 75/150/250 study lists, an Explore hub for the most-used algorithms, an interactive curriculum roadmap, guided Learning courses (like System Design), personal notes, and a weakness map that tracks your readiness.
What do I get with Pro?
Every curriculum layer (DP, graphs, trees, heaps, backtracking and beyond), unlimited new problems, mock interviews, saved code per problem, and the full weakness analytics.
Can I cancel anytime?
Yes. Monthly is month-to-month, and you can manage or cancel your subscription yourself from Settings via the billing portal. Your spaced-repetition history stays with you either way.