Senior Programmer to System Analyst, Frontend - React
Summary
Senior frontend engineer building modular, responsive UIs with React.js, TypeScript, and RxJS — handling reactive state, REST/WebSocket integration, performance optimization, and testing with Jest. Onsite in Whampoa Garden, Kowloon, Hong Kong.
Salary: $30,000 – $45,000 per month
Key Responsibilities
Frontend Architecture: Design and build modular, responsive, and maintainable user interfaces using React.js, TypeScript, and RxJS / RxReact.
Reactive State Management: Handle complex asynchronous data flows, event streams, and real-time state updates using RxJS Observables and reactive state patterns.
API Integration: Integrate frontend modules with backend REST and WebSocket APIs, ensuring efficient caching, error handling, and latency minimization.
UI/UX Excellence: Work closely with UI/UX designers to translate wireframes and design systems (Figma/Adobe XD) into pixel-perfect frontend code.
Performance Optimization: Diagnose and fix performance bottlenecks (rendering cycles, bundle size reduction, memory leaks, DOM optimization).
Code Quality: Write comprehensive unit and integration tests (Jest, React Testing Library) and participate in peer code reviews.
Requirements & Qualifications
Technical Skills:3+ years of hands-on experience in modern frontend development.
Deep proficiency in React.js (Hooks, Context API, Custom Hooks, Functional Components).
Strong, practical knowledge of RxJS and reactive programming concepts (Observables, Subjects, Pipeable Operators, Memory Management/Unsubscribing).
Expertise in TypeScript, HTML5, modern CSS/Sass, and responsive design systems.
Experience with state management frameworks using or combining RxJS (e.g., RxReact, Redux-Observable, or custom Observable stores).
Familiarity with RESTful APIs, WebSockets, and asynchronous request handling.
Experience with modern build tools and bundle managers (Vite, Webpack, npm/pnpm).
Strong problem-solving mindset with attention to detail for UI precision and user experience.
Good communication and collaboration skills in an Agile/Scrum team environment.
Passion for writing clean, self-documenting, and maintainable code.
Nice-to-Haves
Experience with WebSockets / Server-Sent Events (SSE) for real-time data dashboards.
Knowledge of web performance profiling tools (Chrome DevTools Lighthouse, React Profiler).
Familiarity with CI/CD deployment pipelines for frontend assets (AWS CloudFront, S3, Vercel).