ECHealth Healthcare Booking System
Full-stack healthcare appointment booking platform mini-program within Octopus app, featuring React frontend and Spring Boot backend with AWS integration.
- Role
- Full-Stack Developer
- Type
- Built in my full-time job at Appnovation
- Period
- Oct 2025 to Nov 2025
Built comprehensive healthcare booking system as a mini-program (webapp) within the Octopus app for ECHealth. Developed both React 19 frontend with TypeScript and Spring Boot backend, implementing appointment booking, cart management, checkout flow, and email notification system with AWS SES. Includes automatic database migrations, OAuth2 authentication with token refresh, and bilingual support (EN/ZH-HK).
What I built
- 01Built complete React 19 frontend with TypeScript (1,643 lines) featuring brand selection, product catalog, booking flow, and cart management
- 02Developed Spring Boot 3.4 backend (3,634 lines) with RESTful APIs, OAuth2 + JWT authentication, and automatic token refresh on 401 errors
- 03Implemented AWS SES email notification system with async processing, Thymeleaf templates, and dual notifications (customer + CS team)
- 04Created automatic database schema migration system detecting and converting enum columns from smallint to varchar for API compatibility
- 05Built zero-setup development environment with automatic data population seeding 4 healthcare brands and 30+ services on startup
- 06Deployed to AWS infrastructure with S3 static hosting, CloudFront CDN, Lambda@Edge URL rewriting, and RDS PostgreSQL database
Stories worth telling
5,277 lines of code (39 commits) in 5 days across frontend and backend
Bilingual support (English/Traditional Chinese) with i18next and backend Accept-Language headers
Fixed critical infinite loop bug causing thousands of API calls per second
Zero-setup development with automatic schema migrations and data seeding
Production-ready with comprehensive security (4 CVEs patched), error handling, and AWS deployment
Numbers
- 5,277 lines of code
- 39 commits
- Full-stack
- AWS integrated
Stack
- React 19
- TypeScript
- Java 17
- Spring Boot 3.4
- PostgreSQL
- AWS SES
- AWS S3
- CloudFront
- Material-UI
- Tailwind CSS
- i18next
- OAuth2 + JWT