Flashcards for iPhone and iPad
checkst quizzes you instead of letting you re-read, and brings each card back exactly when you would otherwise forget it. For iPhone and iPad.
Why this works
Why flashcards
In an experiment by Roediger and Karpicke (2006), students retained 56% of a text after one week when they had quizzed themselves, but only 42% when they had re-read it. After five minutes, re-reading still had the lead. That is exactly why it feels so deceptively good.
Why spacing
A meta-analysis of 317 experiments (Cepeda et al., 2006) shows that distributed learning beats massed learning. And the further away the exam is, the larger the gap between repetitions should be. You don't have to calculate that yourself. checkst does.
Source: Cepeda et al. (2006): Distributed practice in verbal recall tasks
Scheduling
checkst schedules with FSRS, the Free Spaced Repetition Scheduler. For each card it estimates difficulty, stability and retrievability, and sets the next due date accordingly. In the open benchmark, FSRS-6 predicts recall significantly better than the classic SM-2.
Creating cards
Paste text, open a PDF or take a photo of a book page. checkst suggests basic or cloze cards, on the device with Apple's Foundation Models or with your own OpenAI key. You go through each card and keep only the good ones.
Source: Apple: Meet the Foundation Models framework (WWDC25)
In split view you have the PDF page and the card editor side by side. No switching back and forth between two apps.
Anki-compatible
Open a .apkg file and checkst imports notes, cards and media, including your study progress if it is contained in the package. Cloze deletions, image occlusion, formulas and furigana look as they do in Anki. Going back works the same way: you export decks again as .apkg.
Source: Anki manual: Packaged decks
Learn together
Start a group, invite people via link or QR code and study the same deck. The leaderboard by week, month or all time shows who has really been learning.
Stay on track
Daily streaks, achievements and a widget showing your due cards on the home screen. It sounds like a gimmick, but it is the reason you open the app again tomorrow.
Sync
checkst saves your collection along with its review history to your private iCloud database, free of charge. By default, the content is visible only to you.
You can download checkst for free from the App Store. checkst Pro costs EUR 4.99 for six months, renews automatically and unlocks sync via your checkst account. Studying, Anki import, iCloud sync and groups cost nothing.
Yes. Export your deck from Anki as .apkg and open the file on your iPhone with checkst. According to the Anki manual, a .apkg package can contain notes, note types, cards and optionally your learning progress. checkst keeps that progress by default; you can reset it during import.
No. checkst is a native app for iPhone and iPad.
With the on-device model, yes: Apple describes that for the local Foundation Models model, processing happens on the device and also works offline. If you use your own OpenAI key instead, the text is sent to OpenAI.
The Free Spaced Repetition Scheduler. It models difficulty, memory stability and retrievability for each card and schedules the next review so that you reach a desired retention rate.
No. You can write every card yourself or import ready-made Anki decks. The AI is a starting point for long lecture notes, not a replacement for thinking. Tips on this can be found in the guide to good flashcards.
