framework-x VS React

Have a look at Framework X (https://framework-x.org). It's barebones, but provides routing and basic request/response handling to build your own stuff upon. It's based on ReactPHP so you can use it as standalone service or use it in shared hosting with FPM, whichever suits you.

Using FrameworkX default hello world example I get 12.4K req/s on my M1. FrameworkX is using ReactPHP. Unless I'm reading activity monitor wrong it's ~10MB idle and 12,5 MB max.

There are many micro-frameworks available like Slim, Mezzio(with Swoole may be), or if you are into async then you can also try Framework X(from core maintainer of ReactPHP). This frameworks have small footprints compare to Laravel, Symfony, etc. Yes, you can't get things like authentication, routing and other out of the box but they can easily be installed and configured to be used.

I saw it was mentioned in the Framework X

As others have mentioned, in certain scenarios using a long-running application server (rather than mod_php/php-fpm) to serve requests can make sense. There are a number of extensions and libraries available that facilitate this with asynchronous code execution - Swoole has already been mentioned but you may also want to check out ReactPHP (not related to JS React, other than they stole the name) and Framework X

The Framework X is an attempt to make ReactPHP into a micro framework, but I see little mention of it.

Framework-x https://github.com/clue/framework-x

With ReactPHP, I've written a couple websocket apps. Worked pretty great for that. https://framework-x.org/ is also a pretty good place to get started for a simple HTTP microservice-type app.

Yeah ReactPHP will do this. I have an event source server running and it was pretty easy (once you get the hang of using react). I had an nginx proxy in front of it for tls. Have a look at https://framework-x.org too

Even though this Generator's side is quite obscure for most PHP developers, it has been extensively explored by well-known libraries, such as ReactPHP and AMPHP, which we will see later on.

ReactPHP is a library that allows you to turn PHP into something like Go or Node.js so that tasks can be performed asynchronously. Note that ReactPHP is just a library that you install with Composer. It doesn’t have cumbersome requirements, such as installing a custom PHP extension; it just works as intended.

ReactPHP is categorized as a low-level dependency for event-driven programming. It features an event loop that supports low-level utilities, such as HTTP client/server, async DNS resolver, streams abstraction, and network client/servers.

So you could either skip the framework entirely and shave of these 10ms per request, or you could turn to something like Laravel Octane or ReactPHP to have a long running application that answers requests without bootstrapping the whole framework each time (which is what Node.js, Python or .NET applications do, the practice of restarting the whole app with every request is quite unique to the PHP community).

I remember calling out the movement to serverside of the frontend framework as reactPHP (I think it's when the remix hype first surfaced) on twitter and realized there's a literal php framework called reactPHP (https://reactphp.org/) since they liked my tweet lol.

https://reactphp.org/ of course.

You could also use something like EventMachine (In ruby), Twisted (Python), Node (JS) or ReactPHP (for PHP) that will use the language and turn it into a web application server, and then you'll have only one long running process that handle all your requests with shared memory. You could even use something more fancy like RoadRunner in the case of PHP.