The Biggest Mistakes Engineers Make in Massive Codebases

Working with large, established codebases is notoriously difficult. This article shares a decade's worth of experience, highlighting the most common and deadly mistake: ignoring existing codebase patterns and focusing solely on clean code for a new feature. Maintaining consistency is paramount; it prevents unexpected issues, slows the codebase's descent into chaos, and enables future improvements. The author also stresses understanding the code's production footprint, being cautious about introducing new dependencies, removing redundant code, working in small PRs, and leveraging team expertise to catch errors. While challenging, mastering large codebases is crucial because they are usually the foundation of a company's most valuable products.