Learning, reimagined
Three steps to deep understanding — no rote memorization required.
Visualize
Watch algorithms execute step-by-step with animated data structures, graphs, and neural network layers.
Understand
Interactive controls let you pause, rewind, change inputs, and see how each decision affects the outcome.
Implement
Write code alongside visualizations. Our integrated editor shows your algorithm's behavior in real-time.
Everything you need to actually master it
See it, practice it, prove it — visualizations, quizzes, and real coding, all in one place.
Interactive visualizations
Step through every operation with animated diagrams you control — pause, rewind, and change the inputs.
Gamified quizzes
4,000+ questions with streaks, instant feedback, and celebrations that make progress feel earned.
Live coding challenges
Write and run real solutions in an in-browser editor, checked against hidden test cases.
Progress & mastery
Earn XP, build streaks, and track your path toward mastery across all six domains.
Interview-ready
FAANG-style interview questions on every topic, from first principles to advanced edge cases.
Always free & open
No paywall, no account required. Learn at your own pace, on any device.