Tool
Docker
Reproducible runtimes: the same PHP, extensions and services on every laptop and in CI.
Docker’s quality is isolation: PHP-FPM, nginx, MySQL, Redis, a mail catcher — declared in Compose, not in a wiki. The particularity for PHP is matching extensions (intl, gd, xdebug) so “works on my machine” dies.
Compose is the day-to-day tool; images and healthchecks are how you keep the stack honest. One project, one compose name, dedicated ports when several apps share a host.
It is not Kubernetes. A senior uses containers to standardise the workspace, then decides separately how production is orchestrated.