FrankenPHP — Modern PHP App Server Built on Caddy

Introduction

FrankenPHP is a modern application server for PHP built on top of Caddy. It embeds PHP directly into the web server as a Go module, eliminating the need for PHP-FPM. This architecture enables features like worker mode for persistent applications, HTTP/3 support, early hints (103), and automatic HTTPS out of the box.

What FrankenPHP Does

• Serves PHP applications without requiring PHP-FPM or a separate process manager
• Provides worker mode that keeps PHP scripts in memory between requests
• Handles HTTPS certificates automatically via Caddy integration
• Supports HTTP/2 and HTTP/3 (QUIC) natively
• Enables 103 Early Hints for faster page loads

Architecture Overview

FrankenPHP embeds the PHP interpreter as a Go module inside Caddy. When a request arrives, Caddy routes it to the embedded PHP runtime, avoiding the overhead of FastCGI communication. In worker mode, a PHP script boots once and handles multiple requests from memory, similar to how application servers work in other languages.

Self-Hosting & Configuration

• Run via the official Docker image or download a standalone static binary
• Configure with a Caddyfile or use the default settings for zero-config operation
• Enable worker mode by specifying a worker script (e.g., Laravel or Symfony entry point)
• Set environment variables for PHP configuration (memory limit, extensions, etc.)
• Deploy behind a load balancer or use Caddy's built-in clustering for high availability

Key Features

• Worker mode keeps applications in memory for significant performance gains
• Automatic HTTPS with Let's Encrypt and ZeroSSL certificate provisioning
• Native HTTP/3 and 103 Early Hints support without extra configuration
• Single binary deployment with no PHP-FPM, nginx, or Apache required
• Full compatibility with existing PHP frameworks (Laravel, Symfony, WordPress)

Comparison with Similar Tools

• PHP-FPM + Nginx — Traditional setup requiring multiple processes; FrankenPHP is a single binary
• Swoole — PHP extension for async processing; FrankenPHP keeps standard PHP compatibility
• RoadRunner — Go-based PHP app server; FrankenPHP embeds PHP in Caddy with native HTTPS
• OpenLiteSpeed — High-performance web server with PHP support; FrankenPHP has simpler setup
• Laravel Octane — Framework-level worker mode; FrankenPHP works with any PHP application

FAQ

Q: Is FrankenPHP compatible with my existing PHP application? A: Yes. Standard PHP applications work without modification. Worker mode may require minor adjustments for stateful resources.

Q: How does worker mode improve performance? A: Worker mode boots your application once and handles multiple requests without re-initializing the framework, reducing response times significantly.

Q: Does FrankenPHP support PHP extensions? A: Yes. The Docker image includes common extensions, and you can compile custom builds with additional extensions.

Q: Can I use FrankenPHP in production? A: Yes. FrankenPHP is production-ready and used by organizations running Laravel, Symfony, and other PHP frameworks at scale.

Sources

• https://github.com/php/frankenphp
• https://frankenphp.dev/docs/