Khai Tee

I built a Telegram-inspired Progressive Web App (PWA) focused on real-time messaging, reliability, and scalable backend architecture.

The application supports direct and group chats, real-time WebSocket messaging, message delivery/read receipts, online presence, push notifications, multiple device sessions, and offline-friendly PWA features.

The backend is built with Go, PostgreSQL, Redis, Docker, and WebSockets, with careful handling of database transactions, concurrency, message history, membership permissions, idempotency, and notification delivery.

I also implemented Web Push notifications using VAPID, background notification workers, Redis-based presence tracking, and production deployment with HTTPS and a custom subdomain.

This project gave me hands-on experience building a messaging system where frontend behavior, APIs, databases, real-time connections, background workers, and deployment infrastructure all need to work together reliably.