Most PHP developers never touch clustering primitives. That’s by design. PHP is share-nothing. Each request starts from zero, and anything shared lives somewhere else. Sessions go in Redis. Cache goes in Redis or Memcached. Locks go in Redis. When you run two app servers, the “cluster” is really two stateless boxes pointed at the same Redis. That works until Redis is the thing you’re trying not to run.

If you’ve only ever run PHP behind nginx, you’ve probably never had to think about how echo reaches a socket. When you embed PHP like ePHPm does, it’s the first thing you have to answer. The answer is a SAPI. There is very little written about implementing one. Most of what I know came from reading sapi/cli, sapi/cgi and sapi/embed in php-src. Then I found out which parts I’d misread. This is the write-up I wanted back in March.

Most of the PHP sites I’d put on ePHPm don’t need a MySQL server. A brochure WordPress, an internal Laravel tool, a preview environment that lives for an afternoon. What they do need is something that looks like MySQL, because mysqli and pdo_mysql are the only database drivers their code has ever been pointed at. I mentioned this in the ePHPm pragmatism post as a one-paragraph “because”. This is the longer version, now that WordPress 7.0 and Laravel 13 both install and…

ePHPm tagged v0.1.0 this week, three months after the first commit. Before the feature list grows any further I want to write down how decisions get made on it. This is mostly for myself. The easiest way to ruin a project like this is to let it turn into a checklist of things other projects have.

Last week I wrote about why ePHPm embeds PHP from Rust and promised the signal bug its own post. Here it is. It’s the kind of bug where the fix is about ten lines and the explanation is the whole post. Nothing in PHP’s embed documentation (there’s barely any) tells you that initializing PHP has process-wide side effects. Those side effects assume PHP is the only thing in the process.

Go is my primary language and has been for a long time. When I started building ePHPm a few weeks ago the obvious move was to write it in Go. ePHPm is a PHP application server. It’s one binary that embeds the real PHP interpreter (libphp, the Zend engine) and puts an HTTP server, TLS, a KV cache and a database proxy around it. A PHP app doesn’t need nginx + php-fpm + Redis to run. FrankenPHP already proved the “PHP inside a Go web server” idea works, and it works well. I…