Recall AI – Flutter Flashcard App with AI Generation, Spaced Repetition In-App Subscriptions

Recall AI is a complete, production-ready Flutter application that helps users learn anything faster using AI-generated flashcards and the proven SM-2 spaced repetition algorithm. Built with clean architecture, Riverpod state management, Firebase backend, OpenAI card generation, and RevenueCat subscriptions — everything you need to launch your own study app on Android and iOS.
✨ Key Features
AI Flashcard Generation — Paste notes, type a topic, or upload a PDF/image. OpenAI (GPT-4o-mini) generates a full deck of flashcards in seconds.
SM-2 Spaced Repetition — The same algorithm used by Anki. Cards are scheduled at the optimal interval for long-term retention (New → Learning → Review → Mastered).
4 Study Modes — Flashcard flip, Multiple Choice (MCQ) with explanations, True/False, and Typing mode (Pro).
OCR Input (Pro) — Snap a photo or upload a PDF. Google ML Kit extracts the text, then AI turns it into a study deck.
AI Study Guide — Per-deck AI-generated overview with key concepts, common mistakes, and memory tips.
Gamification — XP, levels, daily streak tracking with 2× XP multiplier, badges, and mastery percentage per deck.
Analytics Dashboard — Weekly study chart, subject mastery breakdown, level progress bar, and badge showcase.
Deck Sharing & Explore — Share decks with a 6-character code. Browse and import from a public community feed.
Push Reminders — Firebase Cloud Messaging sends daily study reminders to keep users on streak.
In-App Subscriptions — Free, Monthly, Yearly, and Lifetime tiers managed via RevenueCat with a built-in paywall screen.
Dark & Light Theme — Material 3 design with dynamic color scheme. Fully customizable brand color.
4 Auth Providers — Email/password, Google Sign-In, Sign in with Apple, and anonymous guest mode.
Offline / Guest Mode — Guests study locally via SharedPreferences. Authenticated users sync via Firestore.
Portrait-only, phone-first UI — Pixel-perfect Material 3 design with Figtree font.
Screens Included
Splash Screen with brand animation
Onboarding carousel (3 slides)
Sign In / Sign Up (Email, Google, Apple, Guest)
Home Overview — stats card, recent decks, quick start
Deck List — search, sort, filter by subject & mastery
Deck Method Selection — 4 creation modes
Deck Creation — AI generation form with subject, difficulty, card count
Deck Detail — 3 tabs: Flashcards, Stats, AI Study Guide
Deck Edit — add, edit, reorder, delete cards
Study Session — 4 modes with progress header
Study Summary — results, XP earned, mastered cards
Progress / Analytics — level, streak, weekly chart, badges
Profile — account info, subscription status, quick stats
Settings — theme toggle, notifications, sign out
Explore — browse community-shared decks
Import Deck — 6-character share code lookup
Paywall — subscription plans with feature comparison
Tech Stack
Framework: Flutter 3 / Dart 3
State Management: flutter_riverpod
Routing: go_router with route guards
Backend: Firebase Auth, Cloud Firestore, Firebase Remote Config
AI: OpenAI GPT-4o-mini (key stored in Remote Config — no hardcoding)
Monetization: RevenueCat (purchases_flutter)
OCR: Google ML Kit Text Recognition
Design: Material 3 · Figtree font · Teal seed color (#0D9488)
Architecture: Clean architecture per feature (presentation / application / domain / data)
Testing: Unit tests + policy tests included
Subscription Tiers
Free
Max decks: 5
Cards per generation: 15
Character input limit: 2,000
PDF / Image upload (OCR): ✗
Typing study mode: ✗
Deck sharing: 1 deck
Analytics history: 7 days
Monthly ($4.99)
Max decks: Unlimited
Cards per generation: 50
Character input limit: 20,000
PDF / Image upload (OCR): ✓
Typing study mode: ✓
Deck sharing: Unlimited
Analytics history: All time
Lifetime ($49.99)
Max decks: Unlimited
Cards per generation: 50
Character input limit: 20,000
PDF / Image upload (OCR): ✓
Typing study mode: ✓
Deck sharing: Unlimited
Analytics history: All time
⚙️ Requirements to Launch
Flutter SDK 3.x
Firebase project (free tier works fine)
OpenAI API key (added to Firebase Remote Config — no code change needed)
RevenueCat account (free up to $2,500 MRR)
Google Play Console ($25 one-time) for Android
Apple Developer account ($99/year) for iOS + Sign in with Apple
What’s Included
Complete Flutter source code (Android + iOS)
Full offline HTML documentation
Quick Start Guide
Unit tests + policy tests
Clean architecture, well-commented and ready to customize