How I Cut 70% of a Production Frontend Codebase in 3 Days

Last week I deleted more than 50,000 lines of code from Jovian’s production codebase, which handles hundreds of thousands of daily user requests. The removed code represented roughly 70% of our frontend repository, written mainly in Java, React, and Next.js.

Instead of a full rewrite, which would have taken months and introduced countless errors, I opted for a progressive migration. By analyzing Google Analytics data, I identified modules with less than 0.1% of page views and safely removed entire directories containing tens of files and thousands of lines, affecting only 0.1% of users.

Continuing this process, I eliminated screens and pop‑ups accounting for under 0.5% of traffic, reducing the number of tabs from five to one and simplifying page structures. The result was fewer API calls, faster page loads, and a more intuitive user experience.

Throughout the cleanup I kept the Git history to restore anything if needed, and the analytics confirmed that 99.9% of functionality remained intact. The psychological hurdle of sunk‑cost bias was overcome by focusing on measurable usage data.

Ultimately, the massive code reduction lowered maintenance overhead, improved performance, and made future migrations easier, proving that regularly pruning unused code can dramatically benefit large web applications.