Web servers

The request path

browser
  → Caddy on :443          TLS terminates here, using your local CA's certificate
  → shared nginx on :18088  one server block per site, matched by hostname
  → php-fpm pool            one per PHP version, not one per site
  → your code

Caddy is the edge and never talks to PHP directly. nginx serves every site by default, which is why the tenth site costs about as much memory as the first.

Per-site overrides

A site can opt out of the shared nginx:

rex site server myshop.rex apache

Server	Version	On	Use it when
nginx	1.30.4	macOS, Windows, Linux	Default. Shared, fastest, lowest overhead
Apache	2.4.68	macOS only	The project relies on .htaccess
FrankenPHP	1.12.4	macOS and Linux	You want its worker mode or Caddy-style config
OpenLiteSpeed	1.9.3	macOS and Linux	You deploy to a LiteSpeed host and use LSCache

On an operating system without it, an override is refused with a message naming the OS — never offered and then broken. The refusal comes before anything is downloaded: until this release, switching a Windows site to OpenLiteSpeed (or a Linux one to Apache) first tried the download and failed with a download error, instead of the sentence that says why.

An override runs a per-site process on a loopback-only port — 8200–8299 for FrankenPHP, 8300–8399 for Apache, 8400–8499 for OpenLiteSpeed — and the edge routes that hostname to it. The override is never the edge and never binds 443.

Apache and .htaccess

The Apache override ships with AllowOverride All, so .htaccess files work as they do in production.

This is the honest answer to a common question

nginx does not read .htaccess and no local environment can make it. Projects that depend on rewrite rules, auth directives or PHP value overrides in .htaccess need Apache — so rexenv ships Apache rather than suggesting you translate your rules. OpenLiteSpeed reads .htaccess too, on macOS and Linux; see below for how it differs.

FrankenPHP brings its own PHP

The pinned FrankenPHP binary embeds PHP 8.5.8. A site on the FrankenPHP override is served by that runtime — not by the shared php-fpm pools, and not by whatever the site’s PHP version setting says.

So on a FrankenPHP site the PHP version picker is read-only, annotated with what actually serves. It used to be editable, which meant it could show 8.2 on a site being served by 8.5.

A PHP 7.4 site cannot run on FrankenPHP, and is refused

Switching a 7.4 site to FrankenPHP, switching a FrankenPHP site to 7.4, or creating one that way, all fail with the reason rather than succeeding into a lie:

FrankenPHP embeds its own PHP 8.5 and cannot run PHP 7.4. A site on 7.4 would be served by 8.5 instead — silently. Use Nginx or Apache for this site.

Use the shared nginx, or the Apache override, for anything on 7.x.

The gap that is still open

The refusal compares major versions, so it catches 7.4 on a FrankenPHP that embeds 8.5 and does not catch an 8.1 site being served by 8.5.

That is a real honesty gap, it predates 7.4 support, and it is tracked rather than closed — widening the guard today would break FrankenPHP sites that currently work. Until it is fixed: if the exact 8.x minor matters to your project, use nginx or Apache and let the site’s pool serve it.

OpenLiteSpeed

macOS and Linux only — there is no Windows build

On Windows the choice is refused at create and at switch, with the app’s own sentence:

OpenLiteSpeed has no Windows build — it exists for macOS and Linux only. Choose Nginx for this site.

rex site server myshop.rex openlitespeed

The reason to pick it is a LiteSpeed host: the LSCache module ships switched on, so the LiteSpeed Cache plugin works as it does in production, and .htaccess is read. No macOS binary of OpenLiteSpeed existed to ship, so this one is rexenv’s own build, 1.9.3, from pinned sources with a small patch set — the same recipe on macOS and Linux.

Like Apache, it has no PHP of its own: .php goes over FastCGI to the site’s shared php-fpm pool, so the site is served by the PHP version it says it runs. Each site gets its own server root under rexenv’s data folder, with its config, run directory and LSCache storage. The admin console is off, and so is OpenLiteSpeed’s release check.

OpenLiteSpeed reads a .htaccess once

A .htaccess created or edited after the server started is not seen until it restarts. rexenv watches the root .htaccess and restarts the site’s backend when it changes — which covers a WordPress permalink save and an LSCache settings save. An edit to a .htaccess in a subdirectory is not watched: run rex site restart <domain>.

A site with a root .htaccess routes itself, as on any LiteSpeed host; without one, rexenv’s own rules route it. Dotfiles answer 404 either way.

One refusal is specific to it. Per-site environment variables reach PHP through rewrite rules, which can quote a value with ' or " but not both — so a value containing both quote characters is refused when you save it for an OpenLiteSpeed site, or switch a site that has one to OpenLiteSpeed:

env var ‘NAME’: OpenLiteSpeed cannot pass a value that contains both ’ and “ (its rewrite flags have no escape for the quote) — drop one of them, or use another web server for this site