01 Why PHP

Goal

Understand what problem PHP was built to solve, where it fits today, and its real tradeoffs.

The Original Problem

PHP started as a set of tools for generating dynamic web pages — the core model is still visible today: a PHP file is HTML with escape hatches into code (<?php ... ?>), and the runtime is designed around a request/response lifecycle rather than a long-running process. Every request gets a fresh interpreter run; there's no shared in-process state to reason about between requests unless you explicitly reach for one (Redis, a database, etc.).

What You Get

Property	Why it matters
Shared-nothing request model	No stale in-memory state between requests; a crashed request doesn't take the process down
No build step	Edit a file, refresh the browser — no compile/bundle step
Huge standard library	HTTP, files, dates, regex, and more available with zero dependencies
Composer + PSR standards	A real package ecosystem with interop conventions across frameworks
Massive hosting footprint	Cheap, ubiquitous hosting; near-universal support

Where PHP Shines

• Web backends — the language's native habitat; the built-in server and shared-nothing model map directly onto HTTP request handling
• CMS ecosystems — WordPress alone accounts for a large share of all websites, all of it PHP; Laravel and Symfony cover the framework end
• Rapid iteration — no compile step means a very short edit-refresh loop
• Scripting and CLI tools — the same runtime that serves web requests runs standalone scripts (see the CLI Tool track on this site)

Where PHP Is a Weaker Fit

• Long-running processes — the shared-nothing model that helps web requests works against you for daemons/workers; those exist (Swoole, RoadRunner) but are the exception, not the default
• CPU-bound numeric work — no first-class numeric/array-computation ecosystem comparable to Python's or Julia's
• Strict compile-time type guarantees — PHP's type system (added incrementally since PHP 7) is optional and gradual, not the primary safety mechanism the way it is in Rust or Go

Checkpoint

<?php
// Shared-nothing in action: nothing here persists across requests
// unless you explicitly write it somewhere (session, cache, DB).
$counter = 0;
$counter++;
echo $counter; // always prints 1, every single request

Compare this to a long-running Node.js or Go process, where a global variable like $counter really would accumulate across requests — that's the core mental model shift PHP asks for.

Next

Continue to more language topics (types, OOP, error handling, and beyond) as they land — tracked as follow-up work.