PuzzleMint

Mint Your Mind, One Puzzle at a Time.

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Inspiration

Traditional educational apps often fall into two extremes: either dry, monotonous multiple-choice drillers or oversimplified casual games that lack curriculum depth. Students preparing for school boards class 1-12, Olympiads, and competitive exams (SAT,GRE,NTSE) constantly struggle with test anxiety, fragmented study resources, and rote memorization fatigue. Meanwhile, teachers and parents lack fast, on-demand tools to generate engaging revision worksheets.

We asked ourselves: What if mastering high-stakes academic curricula felt as engaging as playing an addictive puzzle game?

This inspired PuzzleMint — an all-in-one gamified EdTech platform engineered to transform vocabulary building, complex STEM diagrams, and competitive exam preparation into an interactive adventure powered by gamified mechanics, smart revision loops, and instant offline accessibility.

With PuzzleMint we are aiming to help students at large so they can master their academics and excel at competitive exams and Olympiads and hence with PuzzleMint will be competing for RevenueCat Peace Prize.

What it does

PuzzleMint — Complete Feature List

PuzzleMint is a Kotlin + Jetpack Compose Android app for interactive educational learning targeting Class 1–12 Indian students, competitive exam aspirants, and vocabulary builders.

🧭 Navigation Architecture

Four floating pill-style bottom navigation tabs:

Tab Description
BrainGym Structured curriculum & competitive test prep hub (8 modes)
Tutors AI/Tutor daily topic revision corner (PRO)
FunLearn Games, puzzles, and interactive challenges (10 modes)
Profile User account, analytics, trophies & premium settings

📚 BrainGym Hub (8 Modes)

1. Practice Questions
  • Class 1–12 Question Bank — 50 curated questions per class level
  • 14 Class Tracks: Class 1–10 + Class 11/12 PCM + Class 11/12 PCB
  • Mixed Question Types: Fill-in-the-Blank (FIB) + Multiple Choice (MCQ) with radio option cards
  • Instant retry on wrong answers — no forced progression
2. Timed Mock Tests
  • 25 questions per session across Easy, Intermediate, and Hard levels
  • Official +4 / −1 Scoring out of 100 marks (Correct +4, Wrong −1, Skipped 0)
  • Per-question countdown timers: 10s for MCQ, 20s for FIB
    • Animated color-coded bar: Green → Yellow → Red; auto-advances on timeout
  • Up to 3 Hints per session
  • Early exit with instant score report ("End & Score" button)
  • Detailed Report Card: animated score badge, grade classification (A+ / A / B / C)
  • Best score tracked per Level in SharedPreferences; synced to Firestore
3. Custom Mock Tests (PRO)
  • Build your own test: choose subjects (Mathematics, Science, Mental Ability/NTSE, General & Vocabulary)
  • Configurable: question count (default 20), positive marks (default 4.0), negative marks (default 1.0), time limit (default 30 min; 0 = unlimited / print mode)
  • PDF Export: multi-page A4 PDF with OMR-style answer blanks + full solutions page
  • Creator Trophy badge unlocked on first use
4. Competitive BrainGym (PRO)
  • 3 grade divisions: Primary (Classes 1–5), Secondary (6–10), Senior (11–12)
  • 9 sub-sections per division
  • Two tabs: Daily Puzzles (today's 2 questions) + Target Divisions (past questions by track)
  • Day system: Day 1 = Sept 7, 2026 5:00 AM IST; new day unlocks at 5:00 AM daily
  • Answers saved + synced to Firestore
5. Maths Olympiad
  • IMO-style, Classes 1–10, 35 questions per class
  • Multiple-choice format with full explanations
  • External PDF papers bundled (Class 1–10, 10 PDF files)
  • Best score tracked per class
6. NTSE (National Talent Search Examination)
  • 100-question full paper: 75 MAT + 25 SAT
  • MAT topics: series, analogies, coding-decoding, blood relations, directions, Venn diagrams, dice, clocks, calendars, seating arrangements, syllogisms
  • SAT topics: Physics, Chemistry, Biology, History, Geography, Polity, Economics, Maths
  • Best score tracked globally
7. Science Olympiad
  • NSO / NSTSE / IJSO / NSEJS style questions
  • Classes 1–12, Biology / Physics / Chemistry
  • Best score tracked per OlympiadClass + separate JuniorClass tracking
8. CBSE Board Sample Papers (Class 10 & 12)
  • Official SQPs with marking schemes
  • Class 10 subjects: Science, Maths, English, Social Science, Hindi
  • Class 12 subjects: Physics, Chemistry, Maths, Biology, English, Computer Science, Physical Education
  • Mixed question types: MCQ, SHORT_ANSWER, LONG_ANSWER with marking keywords + explanations
  • PDF export supported

🎮 FunLearn Hub (10 Modes)

9. Daily Challenge
  • 90+ curated daily riddles cycling across: Science, Maths, English, History, Civics, Physics, Biology, Chemistry, Geography, Astronomy, Economics, Literature, Logic, GRE Verbal, Commerce
  • 🔥 Streak Tracker: consecutive daily login tracking
  • Some riddles are MCQ; others are open fill-in-the-blank
10. Vocabulary Vault
  • 4,000+ vocabulary flashcards covering all subjects and levels
  • Interactive 2-sided flip cards: Word & Topic ↔ Definition + Sentence in Context
  • ⭐ Favorites (Bookmark) Deck for targeted revision
  • Explored tracking: remembers which cards have been seen
  • TTS audio pronunciation on every flashcard
11. Vocab Flip Match (PRO)
  • Memory card matching game: flip cards to pair words with their correct meanings
  • Best score (fewest flips) tracked per class key
  • Vocab Genius badge unlocked on completion
12. Special Rewarding Quiz
  • Daily quizzes with bonus rewards on completion
  • Dynamic 200-question pool per class, Class 1–12 aligned
  • Attempt counter tracked per user
13. Rapidfire
  • True/False speed quiz against the clock
  • Classes 1–12 (PCM/PCB streams for senior classes)
  • Some questions include diagram references
  • Speed Demon badge for top performers
14. Match the Columns
  • Connect Column A concepts to Column B answers (classic exam format)
  • Classes 1–12 (PCM/PCB), with diagram integration
  • Master Matcher badge for completion
15. Spelling Bee 🐝
  • 60-second timer per word
  • 3 difficulty tiers: Easy (3–4 letters), Medium (5–7 letters), Tough (8–15 letters)
  • TTS auto-pronounces word; user spells via tile-tap or keyboard
  • Spelling Champ badge for top performers
  • Best score tracked globally
16. Word Search (PRO)
  • Hidden-word puzzle grids — find and tap/drag words in interactive letter matrices
17. Science Diagrams (Diagram Lab)
  • 4 difficulty levels mapped to distinct science diagrams
  • 20+ diagrams rendered purely in Jetpack Compose Canvas (no image assets):
    • Sun, Water Cycle, Plant Cell, Animal Cell, Human Heart, Human Eye, Human Ear, Digestive System, Respiratory System, Reproductive System, Nervous System, Kidney, Skeletal System, Muscular System, Skin Layer, Leaf Cross-section, Flower Parts, Seed Germination, Photosynthesis, Atom Structure, DNA Helix, Electromagnetic Spectrum, Solar System, Weather Cycle, Rock Cycle, Food Chain, Ecosystem Pyramid, Mitosis Stages
  • Drag labels to correct hotspot positions on diagrams
  • Diagram Expert badge for completion; best score tracked
18. Spot the Flaw (Error Hunter)
  • 100 questions spanning Classes 1–10
  • User taps the wrong step in a multi-step math / science / logic solution
  • Then selects the correct replacement from options
  • Best score tracked globally

🎓 Tutors Tab

19. Daily Topics / Tutors Corner (PRO)
  • Subject-wise daily lesson topics aligned to CBSE curriculum
  • 360 Mathematics topics + 360 Science topics (detailed theory generation per topic)
  • Powered by DailyTopicRepository.kt
20. Improvement Questions (PRO)
  • Wrong answers from all test modes auto-collected
  • Spaced-repetition cycling: rotating offset cycles through mistakes (up to 5 at a time)
  • Mastery tracking + topic filter
  • Powered by ImprovementQuestionsScreen.kt
21. Question Vault / Starred Questions (PRO)
  • Bookmark any question from any mode using the ⭐ star icon
  • Persisted in SharedPreferences as JSON; cloud-synced for signed-in users
  • Filterable by topic in a dedicated Vault screen

🔤 Question Types Supported

#### Type Used In
1 MCQ (4 options) All modes
2 Fill-in-the-Blank Practice, Mock Tests, Daily Challenge
3 True / False Rapidfire
4 Match the Columns Match Columns mode
5 Tile-tap Spelling Spelling Bee
6 Error Identification Spot the Flaw
7 Diagram Labeling (drag-to-hotspot) Diagram Lab
8 Short Answer / Long Answer CBSE Board Papers
9 Competitive 2-question Puzzles Competitive BrainGym

📖 Subjects Covered

Subject Area Coverage
Mathematics Classes 1–12, 30 topics/class = 360 total topics (arithmetic → calculus)
Science / EVS Classes 1–8 integrated; 360 topics total
Physics Classes 9–12 (Mechanics, Optics, Electricity, Modern Physics)
Chemistry Classes 9–12 (Organic, Inorganic, Physical Chemistry)
Biology Classes 9–12 (Cell biology, Genetics, Anatomy, Ecology)
Computer Science Class 12
Physical Education Class 12
English Classes 1–12 (Grammar, Literature, Vocabulary, Figures of Speech)
Social Studies Classes 1–10 (History, Geography, Civics/Polity, Economics)
Mental Ability NTSE MAT: series, analogies, coding-decoding, blood relations, etc.
GRE / SAT Verbal Advanced vocabulary and verbal reasoning
General Knowledge Logic, Astronomy, Commerce, World History

👤 Profile & Personalization

22. User Account
  • Google Sign-In via Firebase Auth + Android Credential Manager (1-tap)
  • Guest Mode: full free-tier use without sign-in
  • Editable display name (max 25 chars) synced to SharedPreferences, Firestore & Firebase Auth
  • On logout: RevenueCat logout + Firebase sign-out + guest state sanitization
23. Learning Analytics
  • recordTestAttempt() logs: test name, score, totals, correct/wrong/skipped counts, timestamp
  • History stored as JSON array in SharedPreferences
  • Dedicated screen with subject-wise accuracy, speed insights, and streak data
24. Smart Revision (PRO)
  • Spaced repetition of missed questions with Smart Revision Overlay Dialog
  • Mastery tracking with answer reveal
  • Powered by SmartRevisionOverlayDialog.kt
25. Trophy Cabinet
  • 10 earnable badges shown with locked/unlocked state:
Badge Emoji Unlock
Quiz Specialist 🧠 Complete special quizzes
Spelling Champ 🐝 Ace Spelling Bee
NTSE Scholar 🎓 Complete NTSE sessions
Olympiad Medalist 🏅 Complete Olympiad sets
Speed Demon ⚡ Win Rapidfire rounds
Master Matcher 🧩 Complete Match Columns
Mock Titan ⏱️ Complete mock tests
Creator Trophy 🛠️ Use Custom Mock Generator
Vocab Genius 🎴 Complete Vocab Flip Match
Diagram Expert 🧪 Complete Science Diagrams
26. Localisation support
  • Puzzlemint now supports multi language localisation (German, French, Spanish, hindi,Dutch) allowing users to switch langugage from the profile section.

☁️ Cloud Sync & Persistence

  • Google Cloud Firestore syncs: practice progress, streaks, mock scores, improvement questions, bookmarks, user name
  • Progress survives app uninstalls; works across multiple devices
  • Local SharedPreferences (puzzlemint_progress) for offline-first caching
  • CloudProgress.kt handles all Firestore read/write operations; ProgressStore.kt handles local layer

🔊 Audio & Voice Features

  • Native Text-to-Speech (TTS) on every Riddle Card and Flashcard (🔊 Speaker button)
  • Hear pronunciation of words, definitions, clues & context sentences
  • 100% offline — Android OS TextToSpeech API, US English locale (TTSManager.kt)
  • Voice input for Spelling Bee via Android RecognizerIntent

📤 Sharing & Export

  • Score Card Sharing: branded 900×1600 px bitmap card (Android Canvas) with circular score, grade, correct/wrong/skipped stats, user name & watermark; shared via native share sheet
  • PDF Export: multi-page A4 PDF generated on Android Canvas (no third-party library) with exam header, OMR-style answer blanks, and full solutions page; shared via FileProvider

💰 Monetization

Premium Subscription (RevenueCat)

  • Monthly: ₹9/month (premium-monthly)
  • Annual: ₹99/year (premium-yearly)
  • 1-day free trial available
  • Entitlement: premium_access

Rewarded Ads (InMobi)

  • Optional, never forced — watch to unlock PDF export / Vault Day Pass
  • Max 3 hint-ads per mock test session
  • No banner or interstitial ads — ad-free experience otherwise

PRO-Gated Features Summary

Feature Gate
Competitive BrainGym PRO
Improvement Questions (Smart Revision) PRO
Tutors Corner (Daily Topics) PRO
Word Search PRO
Question Vault (Starred Questions) PRO
Vocab Flip Match PRO
Custom Mock Generator PRO
Smart Revision Overlay PRO

🔔 Notifications & Engagement

  • Firebase Cloud Messaging (FCM): topic daily_arena_reminder, subscribed on app open
  • Custom DailyArenaMessagingService handles push payloads with deep-link navigation to target screen
  • AlarmManager fallback: DailyArenaAlarmReceiver fires daily at 5:00 PM as FCM backup
    • Notification: "Your daily challenge is ready! 🔥"
  • Android 13+ notification permission prompt on first launch
  • Force Update System: checks remote backend on launch; non-dismissible ForceUpdateDialog if mandatory update required, links to Play Store

📦 Content Scale Summary

Content Area Scale
Practice Questions 50 per class × 14 class tracks = 700+ questions
Vocabulary Flashcards 4,000+ words
Daily Challenge Riddles 90+ curated riddles (cycling daily)
Timed Mock Questions 25 × 3 levels
Maths Olympiad 35 Qs × 10 classes = 350 questions
NTSE 100 questions (MAT + SAT)
Science Olympiad NSO Class 1–12 question bank
CBSE Board Subjects 5 (Class 10) + 7 (Class 12)
Special Quiz Pool 200 questions per class
Error Hunter 100 multi-step flawed solutions
Spelling Bee Words 3-tier audio word bank
Match Columns Sets Class 1–12 multi-subject sets
Science Diagrams 20+ diagrams (Canvas-drawn)
Daily Topics 720+ theory topics (360 Maths + 360 Science)
Rapidfire Statements Class 1–12 True/False question bank

🏗️ Technical Stack

Component Technology
Language Kotlin
UI Framework Jetpack Compose (Material 3)
Architecture Single Activity + Compose Navigation
Auth Firebase Auth + Google Credential Manager
Database Google Cloud Firestore
Analytics Firebase Analytics
Subscriptions RevenueCat
Ads InMobi Rewarded Ads
TTS Android native TextToSpeech API
Min SDK API 24 (Android 7.0)
Target SDK Android 13+

How we built it

  • UI & Architecture: Developed 100% in Kotlin using modern Jetpack Compose (Material 3) for fluid, declarative UI, custom Canvas-rendered diagram tools, and smooth card-flip animations.
  • Cloud & Auth: Integrated Firebase Authentication ( with Android Credential Manager) and Cloud Firestore for real-time progress, streaks, mock scores, and vault favorites synchronization.
  • Offline-First Data Layer: Implemented an offline cache store (ProgressStore) ensuring zero-latency offline gameplay and automatic reconciliation upon reconnecting.
  • Audio Engine: Leveraged the native Android TextToSpeech API (TTSManager) to provide zero-latency, 100% offline US English voice pronunciations.
  • Document Engine: Built a custom PDF layout and pagination renderer (TutorPdfHelper / PdfExporter) utilizing Android's low-level PdfDocument graphics canvas to render crisp printable worksheets.
  • Monetization & Push Notifications: Integrated RevenueCat for subscription paywalls and tier entitlements, and Android AlarmManager / NotificationManager for daily engagement reminders.

Challenges we ran into

  • 🚨 The Google AdMob Shutdown & Mid-Shipathon Monetization Pivot:

    • The Crisis: Midway through development, our Google AdMob account faced unexpected closure/suspension, instantly breaking our original "Rewarded Sparks" ad-monetization loop.
    • The Solution: Instead of stalling the project, we executed an agile mid-shipathon pivot: we migrated our core economy to a RevenueCat-powered subscription model (Monthly {₹}9 / Annual {₹}99 with a 1-day free trial) . This transformed an unexpected catastrophe into a far more sustainable, clean, and distraction-free learning experience for students.

  • 📄 Dynamic On-Device PDF Generation: Generating formatted, paginated multi-subject worksheets from raw code with vector diagram alignment and precise typography margins without bloating the APK with heavy third-party rendering libraries.

  • ⚡ Complex State Management & Recomposition in Compose: Managing hundreds of interconnected screens, custom canvas diagram tools, timed mock exam loops, and nested paywall/revision dialogs without dropping frames or losing test state across screen rotations.

  • 🔄 Offline-First Synchronization Integrity: Preventing race conditions and streak loss between local offline caches (ProgressStore) and asynchronous Firebase Firestore writes during intermittent network connectivity.

Accomplishments that we're proud of

  • Agile Pivot Under Pressure: Rapidly architecting and deploying RevenueCat subscription paywalls and freemium entitlement gates after our primary ad network failed mid-hackathon.
  • End-to-End Educational Scope: Building a comprehensive suite that covers Class 1 to 12 curricula, national Olympiads, competitive exams, brain gym mini-games, and educator tooling in a single unified APK.
  • 100% Offline Capability: Native offline Text-to-Speech audio pronunciation and on-device PDF worksheet generation that require zero server calls.
  • Polished, Kid-Safe UX: Clean, distraction-free Material 3 design featuring color-coded countdown timers, celebratory score cards, and seamless signIn.

What we learned

  • Monetization Resilience: The importance of decoupling in-app economies from a single ad provider and designing modular paywall architectures with tools like RevenueCat.
  • Advanced Jetpack Compose Engineering: Techniques for state hoisting, custom Canvas rendering, and optimizing recompositions in high-frequency timer environments.
  • Pedagogical UI Design: How combining high-stakes exam pressure (color-shifting timers, negative marking) with encouraging gamification (streaks, smart revision) significantly elevates learner motivation.

What's next for PuzzleMint

  • 🤖 AI-Powered Remedial Engine: Integrating LLMs to analyze individual student test errors and automatically generate tailored remedial riddles and practice worksheets.
  • ⚔️ Real-Time Multiplayer Arena: Introducing synchronized live quiz duels and classroom leaderboards for school tournaments.
  • 🌐 Multilingual & Regional Curriculum: Expanding curriculum content and TTS pronunciation to regional languages (Hindi, Spanish, etc.) and state boards along with International Curriculam integrated for non Indian students.
  • 📱 Cross-Platform Ecosystem: Bringing PuzzleMint to iOS and Desktop using Kotlin Multiplatform (KMP) / Compose Multiplatform, accompanied by a Web Portal for school administrators and teachers.

Built With

  • android
  • android-credentials-api
  • android-studio
  • android-text-to-speech
  • canvas-api
  • cloud-firestore
  • coroutines
  • edtech
  • exoplayer
  • firebase
  • firebase-analytics
  • firebase-authentication
  • firebase-messaging
  • gamification
  • google-play-billing
  • gradle
  • jetpack-compose
  • kotlin
  • material-design-3
  • pdfdocument
  • picasso
  • revenuecat
  • stateflow
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Updates

posted an update —

Seamlessly switch between crisp Light Mode for daytime study and a soothing, high-contrast Dark Mode for comfortable nighttime practice. Every quiz, puzzle, and study screen adapts dynamically to reduce eye fatigue and save battery life. Enjoy a distraction-free, visually comfortable learning experience tailored to any environment.

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posted an update —

Smart Scan to Solve allows students to snap a photo or upload textbook questions and instantly extract the text using AI-powered OCR. Users can edit, review, and save these problems directly to their personal Question Vault for focused practice. With built-in cloud sync, all your saved questions, answers, and study progress stay seamlessly updated across devices.

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posted an update —

PuzzleMint now supports multi-language localization (including German, French, Dutch, Spanish, and Hindi), allowing users to switch languages seamlessly from their profile settings while preserving their active account session, game progress, and PRO subscription.

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Submission history