caddy-docker-proxy

Caddy-docker-proxy reads your Docker labels and configures Caddy automatically. Add a label to your container saying "this is app.example.com" and caddy-docker-proxy handles the routing, SSL certificate, and renewal. Zero config files.

Fully free under MIT. It's a Caddy plugin that watches the Docker socket for container events and generates Caddy configuration on the fly. Works with Docker Compose and Docker Swarm. Every container gets HTTPS automatically via Let's Encrypt.

The catch: it's Docker-only. If you're on Kubernetes, use Traefik or an ingress controller. The Docker labels syntax has a learning curve. Complex routing rules (path-based routing, headers, redirects) get verbose as labels. And because it watches the Docker socket, it needs elevated permissions, which is a security consideration. For simple setups with 5-15 containers, it's magic. For complex routing, you might want a proper Caddyfile instead.