A step-by-step guide to building a CI/CD pipeline for PHP 8.4 applications using GitHub Actions, Docker, Amazon ECR, and Amazon ECS. Covers project structure, Dockerfile setup, PHP-CS-Fixer and PHPUnit integration, a complete GitHub Actions workflow with four jobs (build-and-test, deploy-to-aws, deploy-pr-preview, teardown-pr-preview), and one-time AWS resource provisioning commands. Pull requests get ephemeral staging environments that are automatically cleaned up on PR close.