Docker Compose Server Setup with FrankenPHP & Caddy Supporting 103 Early Hints

At the 2025 PHP conference, I was introduced to Frankenphp and the Caddy web server. Frankenphp is a PHP service built on the standard PHP we use, with some additional features layered on top. When combined with Caddy web server, it gains support for the 103 Early Hints web response. This 103 status code is not available on the standard Nginx or Apache servers we normally use. What Is 103 Early Hints? This response code allows our browser to begin downloading specified CSS, JavaScript, or certain images before the website has fully loaded. In other words, when we make a request to the site, these assets start downloading before the site’s own HTML response arrives, thereby improving the site’s preload speed. We achieve this in PHP with headers_send(103);, but this is not available in standard PHP. If you try to call this function there, you’ll encounter a PHP Fatal error: Uncaught Error: Call to undefined function headers_send(). This function comes built into Frankenphp.On my Laravel site, I created the following middleware to test it; shortly I will refactor this to be dynamic so it pulls files from whatever theme is currently active. namespace App\\Http\\Middleware; use Closure; use Illuminate\\Http\\Request; use Symfony\\Component\\HttpFoundation\\Response; class EarlyHintsMiddleware { /** * Handle an incoming request. * * @param \\Closure(\\Illuminate\\Http\\Request): (\\Symfony\\Component\\HttpFoundation\\Response) $next */ public function handle(Request $request, Closure $next): Response { $this->frankenphp_send_early_hints([ \'; rel=preload; as=style\', \'; rel=preload; as=style\', \' ; rel=preload; as=style\', \' ; rel=preload; as=style\', \' ; rel=preload; as=style\', \' ; rel=preload; as=style\', \' ; rel=preload; as=style\', \' ; rel=preload; as=style\', \' ; rel=preload; as=style\', \' ; rel=preload; as=style\', \' ; rel=preload; as=script\', \' ; rel=preload; as=script\', \' ; rel=preload; as=script\', \'; rel=preload; as=style\', \'; rel=preload; as=script\', \' ; rel=preload; as=font; type=font/woff2; crossorigin\', \' ; rel=preload; as=font; type=font/woff2; crossorigin\', \' ; rel=preload; as=font; type=font/woff2; crossorigin\', \' ; rel=preload; as=font; type=font/woff2; crossorigin\', ]); return $next($request); } private function frankenphp_send_early_hints(array $links): void { foreach ($links as $link) { header(\'Link: \'.$link); if(function_exists(\'headers_send\')){ headers_send(103); } } } } Now, the main point I want to address is this: I was already planning to move my entire server setup into a Docker Compose–driven architecture, and upon discovering Frankenphp I began building this new structure. That meant moving away from standard Nginx, Apache, and PHP-FPM. Along the way I ran into some issues: some of my sites use outdated software and rely on .htaccess rules that Caddy doesn’t support, causing everything except the homepage to return 404 errors. As a workaround, I found myself adding an Apache service into the Docker Compose. Here is the docker-compose.yaml file I ended up with: services: alpha_panel_web: build: context: ./alpha-panel/web dockerfile: Dockerfile container_name: alpha_panel_web hostname: alpha_panel_web restart: always volumes: - ./alpha-panel/web/httpdocs:/var/www/AlphaPanel/httpdocs - ./alpha-panel/web/logs:/var/log/caddy - ./alpha-panel/web/ssl:/var/www/ssl - ./alpha-panel/web/Caddyfile:/etc/frankenphp/Caddyfile - ./alpha-panel/web/caddy_data:/data - ./vhosts:/var/www/vhosts environment: PANEL_DOMAIN: ${PANEL_DOMAIN} CF_API_TOKEN: ${CF_API_TOKEN} ADMIN_EMAIL: ${ADMIN_EMAIL} ports: - \"${PRIVATE_NETWORK_IP}:7443:443\" networks: - vhost_network alpha_panel_webhook: build: context: ./alpha-panel/webhook dockerfile: Dockerfile container_name: alpha_panel_webhook hostname: alpha_panel_webhook restart: always volumes: - ./alpha-panel/webhook:/app - ./vhosts:/var/www/vhosts - ./alpha-panel/webhook/ssh_key:/root/.ssh networks: - vhost_network frankenphp: build: context: ./frankenphp dockerfile: Dockerfile container_name: frankenphp hostname: frankenphp restart: always environment: CF_API_TOKEN: ${CF_API_TOKEN} ADMIN_EMAIL: ${ADMIN_EMAIL} PUBLIC_NETWORK_IP: ${PUBLIC_NETWORK_IP} PRIVATE_NETWORK_IP: ${PRIVATE_NETWORK_IP} volumes: - ./frankenphp/Caddyfile:/etc/frankenphp/Caddyfile - ./frankenphp/sites-enabled:/etc/frankenphp/sites-enabled - ./frankenphp/caddy_data:/data - ./vhosts:/var/www/vhosts - ./php-code-server/run/:/run/php/ - ./frankenphp/logs:/var/log/caddy/ networks: - vhost_network depends_on: - mysql - redis - mongodb - ftp - meilisearch ports: - \"${PUBLIC_NETWORK_IP}:80:80\" - \"${PUBLIC_NETWORK_IP}:443:443\" php-code-server: build: context: ./php-code-server dockerfile: Dockerfile container_name: php-code-server hostname: php-code-server restart: always user: root environment: - PASSWORD=${CODE_SERVER_PASSWORD} - SUDO_PASSWORD=${CODE_SERVER_SUDO_PASSWORD} - PROXY_DOMAIN=${CODE_SERVER_DOMAIN}:7443 - DEFAULT_WORKSPACE=/var/www/vhosts - TZ=Etc/UTC - ALLOW_ROOT=true volumes: - ./php-code-server/run/:/run/php/ - ./vhosts:/var/www/vhosts - ./php-code-server/supervisor.d:/etc/supervisor/conf.d/ - ./php-code-server/8.4/fpm.d/:/etc/php/8.4/fpm/pool.d/ - ./php-code-server/8.3/fpm.d:/etc/php/8.3/fpm/pool.d/ - ./php-code-server/8.2/fpm.d:/etc/php/8.2/fpm/pool.d/ - ./php-code-server/8.1/fpm.d:/etc/php/8.1/fpm/pool.d/ - ./php-code-server/8.0/fpm.d:/etc/php/8.0/fpm/pool.d/ - ./php-code-server/php.ini:/etc/php/8.4/fpm/conf.d/99999-custom.ini - ./php-code-server/php.ini:/etc/php/8.3/fpm/conf.d/99999-custom.ini - ./php-code-server/php.ini:/etc/php/8.2/fpm/conf.d/99999-custom.ini - ./php-code-server/php.ini:/etc/php/8.1/fpm/conf.d/99999-custom.ini - ./php-code-server/php.ini:/etc/php/8.0/fpm/conf.d/99999-custom.ini - ./ftp-config/users.env:/etc/users.env:ro - ./code-server/data:/root - ./apache/sites-enabled:/etc/apache2/sites-enabled - ./apache/conf-enabled/remote_ip.conf:/etc/apache2/conf-enabled/remote_ip.conf - ./apache/conf-enabled/cloudflare.conf:/etc/apache2/conf-enabled/cloudflare.conf - ./apache/conf-enabled/security.conf:/etc/apache2/conf-enabled/security.conf - ./apache/conf-enabled/deflate.conf:/etc/apache2/conf-enabled/deflate.conf - ./vhosts:/var/www/vhosts - ./php-code-server/run/:/run/php/ depends_on: - mysql - mongodb - redis - meilisearch - ftp networks: - vhost_network meilisearch: image: getmeili/meilisearch:v1.14 container_name: meilisearch hostname: meilisearch volumes: - ./meilisearch/data:/meili_data - ./meilisearch/tmp:/tmp restart: always environment: - MEILI_ENV=production - TMPDIR=/tmp ports: - \"${PRIVATE_NETWORK_IP}:7700:7700\" networks: - vhost_network command: [\"meilisearch\", \"--master-key\", \"${MEILISEARCH_MASTER_KEY}\"] mysql: image: mysql:9.3.0 container_name: mysql hostname: db volumes: - ./mysql/data:/var/lib/mysql - ./mysql/conf.d:/etc/mysql/conf.d restart: always environment: MYSQL_ROOT_PASSWORD: ${MYSQL_ROOT_PASSWORD} ports: - \"${PRIVATE_NETWORK_IP}:3306:3306\" networks: - vhost_network # aliases: # - db.niyazi.org redis: image: redis:latest container_name: redis hostname: redis.niyazi.org restart: always volumes: - ./redis:/data ports: - \"${PRIVATE_NETWORK_IP}:6379:6379\" networks: - vhost_network mongodb: image: mongodb/mongodb-community-server:8.0.8-ubuntu2204 container_name: mongodb hostname: mongodb.niyazi.org restart: always user: root volumes: - ./mongodb:/data/db ports: - \"${PRIVATE_NETWORK_IP}:27017:27017\" networks: - vhost_network backlink_service: build: context: ./vhosts/backlink.name/service dockerfile: Dockerfile container_name: backlink_service hostname: backlinkdb restart: always volumes: - ./vhosts/backlink.name/service:/app networks: - vhost_network password: image: \"vaultwarden/server:latest\" hostname: \"${VAULTWARDEN_DOMAIN}\" container_name: password restart: always volumes: - \"./vaultwarden/data:/data/\" environment: - \"DATABASE_URL=mysql://${VAULTWARDEN_DB_USER}:${VAULTWARDEN_DB_PASSWORD}@${VAULTWARDEN_DB_HOST}/${VAULTWARDEN_DB_NAME}\" - \"RUST_BACKTRACE=1\" networks: - vhost_network phpmyadmin: image: phpmyadmin:latest container_name: phpmyadmin hostname: pma.niyazi.org restart: always environment: PMA_HOST: mysql PMA_PORT: 3306 # PMA_USER: root # PMA_PASSWORD: ${MYSQL_ROOT_PASSWORD} networks: - vhost_network ftp: image: delfer/alpine-ftp-server # Alpine + vsftpd, FTPS destekli container_name: ftp-server hostname: ftp-server restart: always ports: - \"${PRIVATE_NETWORK_IP}:21:21\" # komut kanalı - \"${PRIVATE_NETWORK_IP}:21000-21010:21000-21010\" # pasif mod port aralığı environment: # Dış IP veya hostname (PASV yanıtlarında kullanılır) ADDRESS: server.niyazi.org MIN_PORT: 21000 MAX_PORT: 21010 env_file: - ./ftp-config/users.env entrypoint: [\"/init.sh\"] volumes: - ./vhosts:/var/www/vhosts:rw - ./ftp-config/users.env:/config/users.env:ro - ./ftp-config/init.sh:/init.sh:ro networks: - vhost_network networks: vhost_network: name: vhost_network driver: bridge Most of the additional services I use are included here; before running you can remove any services you won’t need. For example, you can remove alpha_panel_web, alpha_panel_webhook, and backlink_service from the YAML file if you’re not using them. I’m leaving the project’s GitHub link below:https://github.com/niyazialpay/AlphaWebServer