Memory leaks in Node.js applications cause gradual performance degradation and eventual crashes, making them critical to identify and resolve in production environments. With over 12 years of Node.js experience since 2014 and as the creator of CoreUI, I’ve debugged memory leaks in numerous backend systems serving millions of requests. Common causes include unclosed database connections, event listeners that aren’t removed, and global variable accumulation. The solution involves using Chrome DevTools heap snapshots to identify leaks and implementing proper cleanup patterns.