Docker Compose is a tool for defining and running multi-container applications on a single Docker host from a declarative YAML file. A compose.yaml lists services (containers to run), networks (user-defined bridge networks that connect them), and volumes (named Docker volumes for persistent state); docker compose up brings the whole stack online in dependency order, and docker compose down tears it back down.
Compose started life in 2014 as Fig, was acquired by Docker and rewritten in Go as Compose v2 (now a docker compose subcommand instead of the separate Python docker-compose binary), and its file format has been standardized as the open Compose Specification. Other tools implement it: Podman’s podman compose, nerdctl, and Kubernetes-focused converters like kompose all understand some subset of the spec.
Its sweet spot is local development of multi-service apps (web + database + cache + worker), CI integration tests, and quick demos — any situation where Kubernetes is overkill but you still need more than one container wired together. For production deployments beyond a single host, most teams graduate to Kubernetes, Nomad, or a managed container service; recent Compose versions do also have limited “deploy to cloud” backends, but the mainstream path is still Compose for dev and Kubernetes for prod, often with the same image definitions used in both.