InterviewOS — Interview Prep

Learn & test 400+ CS interview topics — system design, DSA, networking, databases, OS, security — with quizzes and a Pomodoro.

Ace your next tech interview — one concept at a time. InterviewOS packs 400+ of the most-asked software-engineering interview topics into a beautiful, distraction-free study app that opens right in your browser. Networking, system design, data structures, algorithms, databases, operating systems, security, web, OOP & design patterns, DevOps — every concept gets a concise explainer with a real-world analogy, then a quick quiz to prove you've learned it. WHAT'S INSIDE 📖 Learn mode — crisp explanations, real-world analogies, and key takeaways for every topic ✍️ Test mode — 10-question quizzes with instant feedback and an explanation for every answer 🎯 Interview mode — curated SDE-1 / SDE-2 / SDE-3 question sets with model answers, key points to tick off, and follow-up probes ✅ Revision tracker — three-pass spaced revision: tick a topic each time you revise it, three ticks means interview-ready 🍅 Pomodoro timer — built-in focus sessions with session and minute stats 🔀 Random topic — jump to a random concept for quick drills 🔎 Instant search — find any topic in a keystroke 🎨 Gorgeous UI — light & dark modes with five accent colors TOPIC CATEGORIES Networking · Web · Security · Data Structures · Algorithms · Operating Systems · System Design · Databases · Redis · OOP & Design · DevOps & Tools · Machine Learning · and more — 400+ topics and growing. PRIVATE & OFFLINE No account, no sign-up, no tracking, no ads. Everything runs 100% locally in your browser and works fully offline. Your revision progress and focus stats are stored on your device only — nothing ever leaves it. HOW TO USE 1. Click the InterviewOS icon in your toolbar (or press Alt+Shift+I) 2. Pick a topic, read the explainer, then hit Test to quiz yourself 3. Tick a revision box each time you revisit a topic — three ticks = ready 4. Preparing to interview others? Interview mode gives you level-appropriate questions with model answers. Perfect for SDE / SWE interview prep, campus placements, quick pre-interview brush-ups, and daily CS revision.