Containerization has changed the way most developers build web apps. Instead of dealing with configuration headaches, you can package everything your app needs into a single and portable container. Docker is like a toolkit to keep everything isolated and reproducible, while Docker Compose lets you spin up several services with one simple file. In our experiment, we set up a two-tier web app and ran it on different operating systems. We found that Linux hosts delivered snappier performance for CPU and disk writes—probably thanks to direct kernel access. Windows and macOS were a bit slower due to virtualization layers. Still, Docker Compose made managing all the moving parts a breeze, and apps ran reliably on every platform we tested.