Docker & Compose

At the end myapp.subdy.io serves your container over HTTPS.

Point the subdomain at your host's IP (dashboard or API), then put Caddy in front of your app:

compose.yml (Compose v2, Caddy 2.8)

services:
  app:
    image: ghcr.io/you/your-app:latest
    expose:
      - "3000"

  caddy:
    image: caddy:2.8
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - ./Caddyfile:/etc/caddy/Caddyfile:ro
      - caddy_data:/data

volumes:
  caddy_data:

Caddyfile

myapp.subdy.io {
    reverse_proxy app:3000
}

docker compose up -d — Caddy obtains the certificate via HTTP-01 as soon as myapp.subdy.io resolves to this host.

Dynamic home IP

If the host sits behind a changing IP, add a dyndns side-car that calls the dyndns2 endpoint every 5 minutes:

compose.yml (fragment)

  dyndns:
    image: curlimages/curl:8.9.1
    command: >-
      sh -c 'while true; do
        curl -sS -u "you@example.com:$$SUBDY_TOKEN"
        "https://api.subdy.io/nic/update?hostname=myapp.subdy.io";
        sleep 300; done'
    environment:
      SUBDY_TOKEN: ${SUBDY_TOKEN}

Without myip the API uses the request's source address — exactly what you want behind NAT.

Dynamic home IP

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