Mobile C# learning app with lessons, quizzes, coding tasks and progress tracking
C# Course is an advanced pre-launch mobile learning platform for learning C# through structured lessons, interactive quizzes, practical coding exercises, progress tracking and gamification. The product is built with Flutter and Firebase and is currently focused on Android. It is designed as a real subscription-based educational product rather than a simple course template or UI prototype. WHAT IS ALREADY BUILT Learning experience • Structured C# course content with progressive learning paths • Lessons organized into sections, topics and stages • Interactive multiple-choice quizzes • Practical coding exercises and code-based challenges • Explanations and learning feedback • Course progress tracking • Lesson completion logic • Progress indicators and completion states • Practice/test section • Learning streak system • Daily progress and gamification features • Unlockable/progression-oriented learning experience User experience • User registration and authentication • Google Sign-In support • User profiles • Persistent learning progress • English localization • Polish localization • Ukrainian localization • Russian localization • In-app language switching • Light and dark themes • Responsive Flutter UI • Accessibility/reduced visual effects support • Account and privacy-related flows Premium & subscription system • Direct Google Play Billing integration • Subscription product and multiple base plans • Monthly, three-month and annual subscription architecture • Server-side purchase verification • Backend-owned purchase acknowledgement • Subscription restoration • Subscription plan changes • User-to-purchase ownership protection • Duplicate purchase protection • Premium entitlement management • Server-authoritative premium access • Google Play Real-Time Developer Notifications integration • Automatic entitlement reconciliation through the Google Play Developer API Backend & infrastructure • Firebase Authentication • Cloud Firestore • Firebase Functions backend • Firebase App Check protection • Google Play Developer API integration • Pub/Sub integration for Google Play RTDN • Backend entitlement reconciliation • Secure token handling • Purchase-token hashing instead of storing raw purchase tokens • Production-oriented security checks and validation • Automated backend tests • Automated Flutter tests • Release validation tooling • Google Play / Data Safety preparation documentation ARCHITECTURE Android app → Google Play Billing → Firebase Functions → Google Play Developer API → Firestore premium entitlement Google Play subscription events → Real-Time Developer Notifications → Pub/Sub → Firebase Functions → Google Play Developer API → entitlement reconciliation Google Play and the backend are authoritative for subscription status, reducing reliance on client-side purchase state and providing a much stronger foundation for a production subscription app. TECH STACK • Flutter / Dart • Firebase Authentication • Cloud Firestore • Firebase FunctionsC# Course is an advanced pre-launch mobile learning platform for learning C# through structured lessons, interactive quizzes, practical coding exercises, progress tracking and gamification. The product is built with Flutter and Firebase and is currently focused on Android. It is designed as a real subscription-based educational product rather than a simple course template or UI prototype. WHAT IS ALREADY BUILT Learning experience • Structured C# course content with progressive learning paths • Lessons organized into sections, topics and stages • Interactive multiple-choice quizzes • Practical coding exercises and code-based challenges • Explanations and learning feedback • Course progress tracking • Lesson completion logic • Progress indicators and completion states • Practice/test section • Learning streak system • Daily progress and gamification features • Unlockable/progression-oriented learning experience User experience • User registration and authentication • Google Sign-In support • User profiles • Persistent learning progress • English localization • Polish localization • Ukrainian localization • Russian localization • In-app language switching • Light and dark themes • Responsive Flutter UI • Accessibility/reduced visual effects support • Account and privacy-related flows Premium & subscription system • Direct Google Play Billing integration • Subscription product and multiple base plans • Monthly, three-month and annual subscription architecture • Server-side purchase verification • Backend-owned purchase acknowledgement • Subscription restoration • Subscription plan changes • User-to-purchase ownership protection • Duplicate purchase protection • Premium entitlement management • Server-authoritative premium access • Google Play Real-Time Developer Notifications integration • Automatic entitlement reconciliation through the Google Play Developer API Backend & infrastructure • Firebase Authentication • Cloud Firestore • Firebase Functions backend • Firebase App Check...
Next step: <p>The buyer can take the project further by completing final QA and UI polish, publishing the Android app on Google Play, expanding the C# course content, adding more coding exercises and quizzes, and investing in user acquisition and marketing.</p><p><br></p><p>The existing architecture can also be extended with additional programming courses, more languages, new premium plans, analytics, notifications, achievements, and further gamification features.</p><p><br></p><p>Because the core mobile app, backend, authentication, progress system, localization, subscription infrastructure, and server-side Google Play verification are already implemented, the buyer can focus primarily on launch, content expansion, branding, and growth rather than rebuilding the technical foundation.</p>
For sale
Asking price: $5,000 USD
What's included
Source code, All related design work, All related data, Email account, Domain name
The sale includes the complete Flutter application source code, backend source code, C# course content, localization files, automated tests, technical documentation, subscription and entitlement architecture, Firebase Functions code, release/security validation tooling, and project-specific design assets. The project includes the existing learning platform, course structure, lessons, quizzes, coding exercises, progress systems, gamification, localization, subscription infrastructure, and supporting backend components. I can also provide reasonable handover assistance to help the buyer understand the project structure and continue development. I am also open to adapting the project to the buyer's specific requirements. This can include rebranding, UI/UX changes, course content modifications, additional lessons or coding exercises, localization, subscription plans, backend behavior, new features, or preparation for a different market or audience. Because the project already includes the complete course platform, mobile application, backend, subscription infrastructure and extensive C# learning content, it can be customized without rebuilding the core system from scratch. Reasonable handover and minor adjustments can be discussed as part of the sale. Larger buyer-specific development can also be discussed separately depending on the requested scope. No personal accounts, private credentials, API secrets, signing keys, or unrelated personal data are included in the sale.
Reason for selling
I have brought the project to an advanced pre-launch stage and would now prefer to focus on other projects. I am looking for a buyer who can take the existing product through launch, marketing and further growth.
Project metrics
Average Monthly Visitors: Pre-launch
Average Monthly Revenue: Pre-revenue
Average Monthly Downloads: Pre-launch / New project
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