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