A personal finance tracker specifically designed for managing dual-currency assets (KRW/GBP) and calculating financial survival. Unlike traditional budgeting apps, it works backward from a target end date to answer: "Given my current savings, what is my daily spending ceiling?"

Managing finances in a foreign country without a local income source presents unique challenges. Runway Tracker was built to address two primary needs:

• Runway-Centric Budgeting: Living on fixed savings (KRW) that must be converted into a local currency (GBP) requires a "runway" mindset. This app focuses on the future—calculating exactly how much you can afford to spend daily or weekly to reach your target date without exhausting your funds.
• Receipt Digitisation: To eliminate the clutter of physical paper receipts, the app allows users to upload and store receipt images for every transaction, maintaining a clean, digital financial record.

• Dual-Currency Runway Calculation — Integrated KRW and GBP balance tracking to calculate remaining days and dynamic daily budget limits.
• Deterministic GBP Balance — Ensures data integrity by calculating GBP balance as: Initial + Total FX Deposits − Total Transactions.
• Smart Exchange Integration — Fetches live KRW/GBP rates via Frankfurter API with daily caching.
• Transaction Management — Organised views for GBP spending and KRW exchange records with manual category tagging.
• Mobile-First Design — A refined, purple-grey design system optimised for mobile browsers (430px max-width) using the Plus Jakarta Sans typeface.

As an individual developer, accessing official banking APIs in South Korea is often restricted. To overcome this:

The Solution: Instead of direct API integration, the app implements a parsing logic for transaction history PDFs exported from the bank. This allows for accurate data synchronisation while remaining independent of restricted financial APIs.

src/
├── app/               # Routing only — pages, layouts, route handlers
│   ├── (auth)/        # Login, onboarding
│   ├── (dashboard)/   # Protected pages
│   └── auth/callback/ # Supabase OAuth callback
├── components/
│   ├── ui/            # shadcn/ui primitives
│   └── layout/        # BottomNav, SubPageHeader, etc.
├── features/          # Domain modules
│   ├── auth/
│   ├── dashboard/
│   └── transactions/
├── lib/
│   ├── supabase/      # client, server, middleware, types
│   ├── balance.ts     # GBP/KRW reverse-calculation
│   ├── exchange-rate.ts
│   └── runway.ts
└── proxy.ts