Overview
An isolated runtime unit for an application and its dependencies.
Definition
An isolated runtime unit for an application and its dependencies.
Real-world example
Your FastAPI app runs inside an isolated filesystem with only port 8000 exposed; a redeploy replaces the container image while a mounted volume keeps uploaded files.
Common mistake
Writing persistent data inside the container layer instead of a Docker volume - data is lost on redeploy.
Better-PaaS in practice
Every Better-PaaS app is a container. Catalog apps use pinned images; Git apps use images built by Nixpacks or your Dockerfile.
FAQ
Is Docker container only relevant to Better-PaaS?
No. Docker container appears across Docker, cloud platforms, and self-hosted tooling. Better-PaaS exposes the concept in deploy logs, dashboard fields, or docs when it affects your app.