Track My Cash: Building a Secure, Decoupled Ledger with Spring Boot, Vanilla JS, and Gemini

This is a submission for the Built with Google Gemini: Writing Challenge Reusing the side project that I had worked on recently for this Challenge What I Built with Google Gemini I built BookKeeping , a full-stack financial ledger application designed to solve a very specific problem: keeping track of money I lend to friends without needing a bloated, complex accounting tool. The application is a stateless, decoupled Single Page Application (SPA). The frontend is built entirely in Vanilla JavaScript, HTML, and CSS (zero framework dependencies!) and now deployed securely on Google Cloud Run. It communicates with a robust backend powered by Java, Spring Boot 3, Spring Security 6, and a PostgreSQL database hosted on Render. Google Gemini was my pair-programming partner throughout the entire development cycle. Gemini played a massive role in helping me stitch together the tricky parts of a decoupled architecture. Specifically, we used Gemini to: Architect the Security Flow : It helped me i