I wanted to share something I’ve been building, Cards.my. It's a vocabulary flashcard app for iOS - I started it in early 2022 and have been chipping at it on weekends since. At its core, it’s still just flashcards: * folders (topic / level / whatever structure you want) * word pairs (your language ↔ foreign language, optional images) * two study modes: * Learn: self-paced, reveal/hide, free navigation, shuffle anytime * Test: shuffled, typed answers, case-insensitive + trimmed input, instant feedback, no backtracking, final score + retry if performance is bad Nothing novel there - that part is intentionally boring. What ended up making it interesting for me were the small «product correctness» details and constraints that stack up over time: - Pronunciation is fully system-based (AVSpeech). The speaker only appears when iOS actually supports a voice for that language, and the app auto-detects the dominant language per folder so you don’t end up with broken audio buttons everywhere. - There’s a cross-folder review mode («Words you often forget») that aggregates weak cards across the entire library based on actual performance history, not just per-deck repetition. - Folders are portable files. You can export a .cardsmy file and send it via AirDrop / Messages / email, and it just imports on the other side. No account needed. - CloudKit handles full sync, including images. Stats are intentionally not «streak-based gamification». Instead: * 7-day practice strip * mastered / weak word lists * revisit queue based on real errors * reminders that adapt to activity instead of nagging for streak preservation There’s also AI-assisted example generation per card: * tap “Examples” → generates a few usage sentences for the target word * strict guardrails (rate limits, quotas, refusal rules) * explicit “AI may be wrong” labeling everywhere it appears On the engineering side, a lot of effort went into boring reliability work: * debounce search everywhere * undo window for folder deletion (5 days) * stable sort persistence * exam hint system * deep links And then the AI layer, which turned out to be more prompt engineering + validation than UI work: * strict JSON schema enforcement * deduping via normalization (case, whitespace, diacritics) * rejection of invalid scopes («10k words», multi-folder requests, etc.) * language-specific grammar rules where needed Tech stack: * 100% native SwiftUI * CloudKit sync * OpenAI for example sentences (with strict quotas + rate limiting to avoid cost blowups) Free tier: 4 folders, 50 cards each. Subscription unlocks everything with a 7-day trial. No ads, no tracking beyond crash + product analytics. If anyone tries it, I’d genuinely appreciate feedback - especially on: * AI sentence quality edge cases * where the study flow feels unintuitive or too «manual» Happy to share a promo code with anyone who wants to try it and give feedback.

Cards.my

Create cards, test your progress and improve your vocabulary

Create cards, test your progress and improve your vocabulary