Docker networking and volumes explained: how containers communicate and persist data

A technical guide published on DEV Community explains how to enable communication between Docker containers using user-defined bridge networks, which provide built-in DNS resolution by container name. By default, containers are network-isolated from each other, meaning services like an API and a database cannot reach one another unless explicitly connected to the same network. The article also covers Docker's four network drivers — bridge, host, none, and overlay — outlining appropriate use cases for each. On the data persistence side, it addresses the ephemeral nature of container storage, where all written data is lost upon container removal, and demonstrates how named volumes solve this by existing independently of any container's lifecycle. The piece is part of an ongoing series aimed at developers building multi-container applications on a single machine.