Overview
A spaced-repetition flashcard trainer with a five-box Leitner schedule, seeded with cards on algorithms, web, Python, databases, machine learning, cloud, security, and systems topics. You can add your own cards, and the tool tracks due cards, mastery, accuracy, and a daily review streak — all stored in your browser.
How It Works
Review the card shown: click it to flip between question and answer, then rate yourself with Again (you got it wrong) or Got it (correct). Correct answers move a card up one box; misses drop it down and bring it back within ten minutes. The stats row shows due-now count, mastered cards out of the deck, lifetime accuracy, and your streak in days. Use Add card to create your own question-and-answer pairs with a tag, and Reset progress to return the deck to its defaults.
Step-by-Step Usage Guide
- Open the deck and flip the top card to reveal its answer.
- Rate honestly: Got it advances the card, Again brings it back in ten minutes.
- Add your own cards for topics the built-in deck does not cover.
- Check the interval table to see how each box maps to days until review.
Technical Specifications & Standards
The scheduler is a textbook Leitner system with five boxes: box 1 is due immediately, and boxes 2 through 5 schedule the next review at 1, 3, 7, and 30 days respectively. A correct answer promotes one box (capped at 5); a wrong answer demotes one box (floored at 1) and sets a ten-minute retry, so a hard card comes back the same session rather than disappearing for a day. Cards sort by due time with ties broken by lower box, so struggling cards surface first. Mastery counts cards in box 5. The deck, per-card review counts, accuracy, and streak persist under the localStorage key CruxDev-flashcards-v1, validated field by field on load so a corrupted save degrades to defaults instead of crashing. Two boundaries worth knowing: only custom cards can be deleted individually — the eight built-in cards stay unless you reset the whole deck — and the streak counts days with at least one review, not cards reviewed. As with any localStorage app, clearing site data erases your progress.
Targeted Use Cases
- Preparing for technical interviews with repeated exposure to core CS questions.
- Memorising definitions and trade-offs across cloud, security, and database topics.
- Studying a certification syllabus by building a personal deck with tags.
- Keeping a daily review habit with the streak counter as reinforcement.
Notes & Gotchas
- Answer from memory before flipping; recognition feels like knowledge but is not.
- Rate Again truthfully — the scheduler only works if misses actually demote cards.
- Tag custom cards by topic so you can reason about your weak areas.
- Export your knowledge by keeping your own copy of important custom cards; they live only in this browser.
Frequently Asked Questions
How do the Leitner boxes schedule reviews?
Five boxes with intervals of 0, 1, 3, 7, and 30 days: box 1 is due now, and each correct answer moves a card up one box to a longer interval. A miss demotes one box and returns the card in ten minutes.
Where is my deck and progress stored?
In localStorage under the key CruxDev-flashcards-v1, in your browser only. Cards, review history, accuracy, and streak all live there; clearing site data erases them.
Can I delete the built-in cards?
No — only custom cards have a delete button. Use Reset progress to restore the entire deck to its default state, which also clears all review history.
How is mastery measured?
A card is counted as mastered once it reaches box 5, the 30-day interval. The accuracy percentage is your lifetime ratio of correct answers to total reviews across all cards.