Building a Full-Stack Bookkeeping Ledger Using Antigravity

I recently built a full-stack bookkeeping application to help track borrowed money and loan repayments. My goal for this side project was to build a secure, practical tool from scratch while gaining hands-on experience with modern, decoupled application architecture. I usually lend money, and most of the time, I get lost in tracking the records. Since we have modern AI agents and tools, I use Google Antigravity IDE, where my primary focus was to provide the requirements, review the plan put forward by Antigravity, review the code, and provide suggestions. Here is an overview of the project, the tech stack I used, and some of the technical challenges I solved along the way. The Tech Stack I chose to separate the frontend from the backend to mirror how production applications are often built. The project is hosted entirely on cloud-free tiers. Backend: Java, Spring Boot 3, Spring Data JPA Database: PostgreSQL (hosted on Neon.tech) Frontend: Vanilla JavaScript, HTML, and CSS Security: Spr