Learn how to use Docker Compose to define and run multi-container applications with this detailed introduction to the tool. 🔧 What is Docker ? Docker is a platform for packaging applications into containers — lightweight, portable units that bundle your app with its dependencies. Follow this hands-on tutorial to learn how to use Docker Compose from defining application dependencies to experimenting with commands. With Docker Compose you use a YAML configuration file, known as the Compose file, to configure your application’s services, and then you create and start all the services from your configuration with the Compose CLI. The Compose file, or compose .yaml file, follows the rules provided by the Compose Specification in how to define multi-container applications. This is the Docker Compose implementation of the formal Compose Specification.