FlashStacksYour flashcards,
on your Home Screen.
FlashStacks turns study cards into beautiful iPhone widgets. Glance at a question, tap to reveal the answer — without ever opening the app.
Studying that fits into the moments already filling your day
Every time you check your phone, there's something new to learn. No app to open, no friction, no excuses.
Home Screen & Lock Screen widgets
Your cards live where you already look dozens of times a day. Cards rotate automatically — tap to reveal, tap to advance. How widgets work →
AI deck generation from PDF
Upload lecture slides or a textbook chapter and AI builds a complete, study-ready deck in seconds. See how it works →
FlashStacks Learn — 5 languages
5,100 ready-made vocabulary cards in French, Spanish, Japanese, Korean and Mandarin. Tap a pack, and it's on your Lock Screen. Browse the languages →
Spaced repetition built in
The same science behind Anki. Cards you struggle with come back sooner; cards you've mastered fade into the background.
Image occlusion cards
Add diagrams, anatomy, or maps and draw boxes over areas to hide. Tap to reveal what's underneath. Learn more →
Beautiful by design
Every stack gets its own colour palette. Widgets match your stack. Dark mode uses pure OLED black.
Streaks & progress tracking
Per-stack mastery stats, difficulty breakdowns, and 14-day activity. Build a streak and hit your daily goal.
Stop making excuses. Start glancing.
Free to download. Premium unlocks AI generation, language packs, image occlusion, and Lock Screen widgets — with a $2.99 first month.
Frequently asked questions
Is FlashStacks free?
Yes — download, create stacks, add cards, and study with spaced repetition for free. Premium unlocks AI deck generation from PDF, the FlashStacks Learn language packs, image occlusion cards, and Lock Screen widgets.
How does the PDF to flashcards feature work?
Choose any PDF — lecture notes, a textbook chapter, a study guide — and AI reads every page, extracts the key concepts, and writes a complete flashcard deck. You review the cards and import the ones you want.
Does it work on the Lock Screen?
Yes. FlashStacks supports Lock Screen widgets, so a study card is the first thing you see when you pick up your phone.
Is it a good alternative to Anki?
FlashStacks uses the same spaced-repetition science as Anki, but adds Home Screen widgets and AI deck creation, with a modern design. See our full Anki comparison.
What languages does FlashStacks support?
Two different things. The app itself is translated into English, German, Spanish, French, Italian, Japanese, Korean, Portuguese (Brazil), Russian and Simplified Chinese. Separately, FlashStacks Learn teaches French, Spanish, Japanese, Korean and Mandarin — or English, if your phone is set to one of the other nine.
Can I learn a language with FlashStacks?
Yes — FlashStacks Learn includes 5,100 curated vocabulary cards across five languages, shown on your Lock Screen so you pick words up in glances rather than sitting down to study.
Does FlashStacks work offline?
Yes. Your cards, your study history and the language packs all live on your device. The only feature that needs a connection is AI deck generation from a PDF.
Is there an Android version?
Not yet — FlashStacks is built natively for iPhone, which is what makes the Home Screen, Lock Screen, StandBy and Dynamic Island integration possible.
How do I rate a card while studying?
Swipe it. Right means easy, left means hard, and the four buttons (Again, Hard, Good, Easy) are there when you want finer control. Spaced repetition schedules the next review from your answer.
Does FlashStacks cost anything to try?
Downloading and studying your own decks is free with no time limit. Premium is $2.99 for your first month on the annual plan if you want AI generation, language packs, image occlusion or Lock Screen widgets.