A high-concurrency e-learning platform supporting real-time virtual classrooms, instant message boards, and interactive whiteboards scaling to thousands of concurrent users.
Project Context
- Business Domain: EdTech / Virtual Education
- Project Context: Highly scalable, collaborative e-learning platform designed to handle thousands of concurrent students and instructors in real-time.
My Role
My role was as a Full-Stack Developer. I worked on the ASP.NET Core backend utilizing SignalR, integrated the Angular frontend with NgRx for state management, and optimized database queries using SQL Server indexing and caching.
The Challenge
The system needed to support live interactive classrooms, real-time quizzes, and instant message boards without performance degradation during peak hours, scaling to handle thousands of concurrent connections.
Architecture
- Frontend: Angular frontend using NgRx for client-side state management.
- Backend: ASP.NET Core backend utilizing SignalR for WebSockets.
- Database: SQL Server optimized with custom indexing and query caching.
- Real-time Scaling: Designed to support horizontal scale-out for SignalR-based real-time communication.
Technology Stack
Frontend
- Angular
- NgRx
Backend
- ASP.NET Core
- SignalR
Data
- SQL Server
Infrastructure
- Cloud Infrastructure
Key Engineering Challenges
Challenge 1: Real-Time Virtual Classrooms at Scale
- Challenge: Supporting live interactive classrooms, real-time quizzes, and instant message boards for thousands of concurrent users without performance lag.
- Solution: Developed a real-time messaging pipeline utilizing ASP.NET Core SignalR for WebSocket connections and Angular NgRx for frontend state syncing.
- Engineering Impact: Successfully scaled the real-time classroom experience to support thousands of active sessions.
Challenge 2: Relational Database Latency under High Concurrency
- Challenge: High read/write lock contention on the database during real-time quizzes and board updates.
- Solution: Applied database indexing optimizations and query caching strategies in SQL Server.
- Engineering Impact: Reduced backend API response times significantly under peak loads.
Technical Decisions & Trade-offs
- NgRx for Frontend State Management: Chose NgRx to manage real-time synchronized state. This reduced redundant API state requests, though it increased frontend development boilerplate and initial loading footprint.
- SignalR Scale-Out Approach: The architecture was designed to support horizontal scale-out for SignalR-based real-time communication.
Performance & Scalability
- Scaled to support high concurrent connection loads.
- Reduced API response times significantly.
Security
- Secure WebSocket connections.
- Encrypted user sessions.
Outcome
The system successfully scaled to support high concurrent connection loads, reducing API response times significantly and providing a seamless, real-time classroom experience.
Lessons Learned
- Reactive state management (NgRx) on the frontend is crucial to handle high-frequency WebSocket updates without browser lockup.
- Structured relational indexing and query caching are effective baseline optimizations before needing to split databases into microservices.
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About Rajdip Khavad
Rajdip Khavad is an Angular and ASP.NET Core/.NET developer specializing in enterprise applications, APIs, application modernization and performance-focused engineering. On this project, his focus was real-time application architecture and SignalR-based collaboration.