Examio: Endless Practice

Examio is a professionally engineered educational and exam-preparation platform for iOS and Android. The app combines language learning, school subjects, theory materials, generated practice questions, mistake review, in-app purchases, rewarded advertising, and multilingual content. The platform currently has: 8,000 users 10,000+ questions 8 subject areas iOS and Android applications Six supported languages Existing monetization infrastructure Production-ready backend and web components This is a complete product and technical foundation, not a prototype or AI-generated “vibe-coded” project. It was designed and built by a senior software engineer using a structured TypeScript monorepo and established production technologies. Product Overview Examio helps students and independent learners study through a repeatable learning cycle: Choose a subject and topic. Read theory and educational material. Practice generated questions. Receive immediate feedback. Review incorrect answers. Unlock additional content through coins or purchases. Continue practicing with different difficulty levels and question sets. The app supports both traditional school subjects and language-learning content. Its architecture allows new subjects, categories, translations, theory content, questions, offers, and monetization rules to be added without rebuilding the entire application. Current Subject Areas The application includes eight subject families: Czech English French Geography German Mathematics Portuguese Spanish Content includes language vocabulary, grammar, phrasal verbs, prepositions, spelling, geography, flags, capital cities, arithmetic, decimals, inequalities, powers, roots, and more. Key Features Learning and Practice Theory lessons connected to individual topics Generated practice tasks Multiple difficulty levels Randomized and repeatable question generation Immediate answer feedback Correct, incorrect, and skipped answer tracking Dedicated incorrect-answer review Topic and category-based navigation Support for text-based and image-based questions Personalized practice based on previous mistakes Language Learning Six user interface and content languages: English Spanish French Portuguese German Czech Localized subjects, categories, theory, questions, and answer options Separate practice and translation language settings International expansion potential through additional locale files Content Management The backend uses a structured content model: Subjects Subject groups Categories Difficulty levels Theory content Questions Answer options Images Prices and unlock states Localized translations The system includes validation tools for identifying missing translations, invalid references, duplicate answers, and content inconsistencies. The current monetization system supports: Category unlocks Temporary and permanent access In-app coin balance Coins purchased through the app Coins earned through rewarded advertising Apple in-app purchase integration through RevenueCat Stripe Checkout for web payments Promotion codes and multiple currencies Rewarded ads through Google Mobile Ads / AdMob Supported currencies include EUR, USD, GBP, CZK, BRL, and MXN. Marketing Automation The platform includes tools for turning educational content into social media content: Automatic generation of branded quiz images Two-page question posts Instagram publishing integration Scheduled publishing three times per week Potential for organic user acquisition and educational social media marketing You can see the IG here: https://www.instagram.com/examio.app Technical Stack: - Mobile: React Native Expo Expo Router TypeScript iOS support Android support React Native Reanimated React Query Zustand Expo Application Services Google Mobile Ads / AdMob RevenueCat Sentry monitoring - Backend: Node.js Express 5 TypeScript MongoDB Mongoose JWT authentication Google and Apple sign-in Zod request validation Helmet security middleware Structured logging with Pino Scheduled jobs with node-cron Stripe integration RevenueCat webhook handling Sentry server monitoring - Web: Next.js React TypeScript Tailwind CSS Web shop and payment flow Public product pages Vercel-compatible deployment Infrastructure: MongoDB for users, content, sessions, offers, transactions, and learning data Heroku-compatible backend deployment Vercel-compatible web deployment Expo and EAS for mobile builds AdMob for rewarded advertising RevenueCat for mobile purchases Stripe for web payments Sentry for error monitoring AWS/CloudFront-compatible content and image delivery Architecture and Code Quality The project is organized as a Turborepo monorepo with shared packages: Native mobile application Web application Backend API Shared TypeScript types Shared utility functions Shared application constants Shared linting and configuration This structure makes the codebase easier to maintain and extend than a standalone prototype. Shared types reduce inconsistencies between the mobile app, web application, and API. The application includes: Version checks for mobile clients Maintenance mode support Authentication and authorization User banning and account controls Request validation Optional request signing and encryption Payment webhooks Content validation Error tracking Structured logging Multiple payment providers Production build and deployment configurations Commercial Potential: Examio could be expanded in several directions: Add more school subjects Add country-specific exam preparation Add standardized test preparation Add progress dashboards and learning statistics Introduce subscription plans Add teacher, school, or classroom accounts Offer white-label versions for educational organizations Expand the question database Add leaderboards and challenges Add daily streaks and push notifications Add AI-assisted content administration Localize into additional languages Add B2B licensing for schools and tutoring companies Build a larger Instagram, TikTok, and YouTube education funnel The existing architecture is suitable for content expansion, internationalization, and additional monetization models. What the Buyer Receives Depending on the transaction structure, the buyer can receive: React Native iOS and Android source code Expo and EAS configuration Node.js/Express backend Next.js web MongoDB data Question and subject content Localization files Monetization integrations RevenueCat integration AdMob integration Stripe integration Deployment configuration Content validation scripts Instagram publishing automation Shared TypeScript packages Technical documentation and handover support