Memory Leaks in Vibecoded Apps

The primary symptom is performance degradation over time. The app starts fast but becomes sluggish after minutes of use. Scrolling stutters, animations lag, and the browser tab's memory usage climbs steadily in the Task Manager. If closing and reopening the page restores performance, a memory leak is the likely culprit.

Use the Chrome DevTools Performance Monitor to watch JS heap size as you navigate the app. If memory increases with each page navigation and never returns to baseline, components are leaking. The Memory tab's heap snapshot comparison can pinpoint exactly which objects are being retained.

Navigate back and forth between two pages repeatedly — twenty to thirty times. Each navigation should unmount components from the previous page and mount new ones. If memory grows with each cycle, the unmounted components are not being garbage collected because something still references them.

Open pages with real-time features — chat, live updates, dashboards with auto-refresh — and leave them open for several minutes. These features use setInterval, WebSocket connections, or event listeners that must be cleaned up on unmount. AI-generated code almost never includes the cleanup function in useEffect.

Audit every useEffect hook for a missing cleanup function. Any effect that sets up a listener, interval, timeout, or subscription must return a function that tears it down. This is the single most common source of memory leaks in vibecoded React apps.

Use AbortController to cancel pending fetch requests when components unmount. Remove event listeners added to window or document with the exact same function reference used in addEventListener. For third-party libraries, call their cleanup or destroy methods in the useEffect return function.