performance-optimizer

Profile first before optimizing. Use Chrome DevTools Performance tab for frontend long tasks, node --prof for Node.js execution profiling, and EXPLAIN ANALYZE for slow database queries. Fix the slowest component first for the biggest impact.

Replace per-record queries inside loops with a single query using a JOIN or ORM populate call. For example, use db.users.find().populate('posts') instead of fetching posts for each user individually, reducing N+1 queries to one.

High-impact quick wins include adding database indexes, enabling gzip compression, caching expensive operations, lazy loading images and components, using a CDN, minifying assets, paginating large datasets, and converting images to WebP.

Memory leaks often come from event listeners or subscriptions not cleaned up in useEffect. Always return a cleanup function, such as removing the scroll listener, so resources are released when the component unmounts.

Avoid premature optimization and micro-optimizations that save milliseconds on an already fast path. Optimize only when measurements show a real bottleneck, and never sacrifice code readability for negligible speed gains.