Lịch Việt – Vietnamese Lunar Calendar
A Vietnamese solar–lunar calendar app with feng shui & almanac insights across iOS, Android and web.
Main calendar interface with dual Solar–Lunar view
The Challenge
Vietnamese users want a trustworthy digital tool that merges accurate lunar calendar data with practical feng shui guidance for daily decisions. Many existing apps either fall short in calculation accuracy or provide incomplete feng shui information. The goal was a culturally authentic product that works offline-first, runs real-time astronomical calculations reliably, and presents complex traditional concepts in a modern, accessible UI.
The Solution
We built a cross-platform ecosystem using React Native (iOS/Android) and Next.js (web). The lunar-javascript library powers consistent astronomical/lunar calculations across platforms. Pre-bundled feng shui datasets enable offline usage. A proprietary Day Score (0–100%) quantifies how auspicious a day is based on traditional rules. A real-time feng shui compass overlay completes the experience.
Key Features
- Dual calendar view with synchronized Solar & Vietnamese Lunar dates
- Day Score (0–100%) based on 28 Mansions, 12 Day Officers, and traditional feng shui rules
- Auspicious hours (Giờ Hoàng Đạo) with 12 zodiac animal indicators
- Real-time feng shui compass showing Hỷ Thần & Tài Thần directions
- Clear Recommended / Avoid activities (Nên Làm / Không Nên)
- Vietnamese holidays with countdown notifications
- Offline-first architecture with bundled feng shui data
- Accessibility support (reduce-motion preference)
- Firebase Analytics with resilient offline event queuing
Tech Stack
- Mobile: React Native 0.73+ · TypeScript · Zustand · TanStack Query
- Web: Next.js 16 · React 19 · Tailwind CSS · SSR for SEO
- Core: lunar-javascript (astronomical/lunar calculations)
- Analytics: Firebase Analytics with a fail-safe offline queue
- Storage: AsyncStorage · MMKV for fast key-value caching
Get the App
Experience native performance.
