What is PHP? The programming language running the web

A language that works behind the scenes

When you open a page built with WordPress, you’re not reading PHP code: you’re reading its output. PHP (a recursive acronym for “PHP: Hypertext Preprocessor”) is a server-side scripting language, built specifically for web development and embeddable directly into HTML. The official manual draws a sharp line between it and a client-side language like JavaScript: PHP code runs on the server, which generates the HTML and sends it to the browser. Visitors receive the result, never the instructions that produced it.

To work in its most common setup, PHP needs three pieces: a PHP parser, a web server and a browser to receive the output. There’s also a command-line mode, with no server or browser involved, used for scheduled tasks or for processing plain text.

What it can actually do

The list of PHP’s capabilities explains why it became the de facto standard for dynamic websites: it collects data from forms, generates different content on every visit, handles cookies and sessions, produces files in various formats (images, PDFs), encrypts data, sends email, talks to a wide range of databases (MySQL, PostgreSQL and others), processes text with regular expressions, and handles network protocols like HTTP, IMAP or LDAP. It runs on every major operating system and with most modern web servers, from Apache to nginx.

A taste of the syntax, without turning into a course

You don’t need to know how to code to understand PHP, but a couple of details help you recognize it when you see it. Variables always start with a dollar sign, followed by a name that must begin with a letter or underscore; they’re also case-sensitive, so $var and $Var are two different variables. Functions — small algorithms you can call by name — are defined with the keyword function:

Example: a minimal script that defines and uses a variable might look like this:

<?php
$name = "Recaplica";
function greet($who) {
    echo "Hello, $who!";
}
greet($name);
?>

The server runs these lines and sends the browser only the result: “Hello, Recaplica!” No trace of the code reaches the visitor.

From a programmer’s résumé to half the web

PHP was born in 1994 out of a small, concrete need: Rasmus Lerdorf wanted to know who was visiting his online résumé, so he wrote some scripts he called “Personal Home Page Tools.” In June 1995 he published the source code; within months the project changed names a few times before merging into “PHP/FI.” By 1998, when version 3 came out, nearly 60,000 domains were already using PHP — roughly 1% of all domains at the time — and with the announcement of the new version, rewritten by Andi Gutmans and Zeev Suraski, that number climbed to about 70,000.

From there, growth never really stopped, version after version:

Version	Year	Key change
PHP 3	1998	Parser rewrite; the recursive acronym “PHP: Hypertext Preprocessor” is born
PHP 4	2000	Zend Engine; much higher performance, HTTP sessions
PHP 5	2004	Zend Engine 2.0; new object model
PHP 6	never released	Native Unicode support abandoned in 2010 over performance issues
PHP 7	2015	Zend Engine 3; roughly double the performance of PHP 5.6, null coalescing operator
PHP 8	2020	JIT compiler, union types, attributes, match expressions

The empty row for PHP 6 isn’t a typo: the project aimed for deep Unicode support built into the language’s own engine, but it was abandoned because of the performance problems that came with it. Some of the ideas planned for that version — namespaces, for instance — made it into PHP 5.3 and 5.4 anyway, before development jumped straight to version 7.

Who uses PHP in 2026 (and who built on top of it)

According to W3Techs, as of September 2026, 70.2% of websites whose server-side language is known are written in PHP, with Facebook, Wikipedia, WordPress and some Microsoft subdomains among the well-known names that use it. Among PHP sites, version 8 is already the majority (63.4%), followed by version 7 (28.6%) and a long tail of older releases.

On top of the language, frameworks have grown up to structure its use in large projects: Laravel, described by its official site as a “batteries-included” PHP framework, meaning most of the tools you need come ready to use, and Symfony, which bills itself as a “full-stack” framework and has passed 41 billion downloads according to its own site. Symfony also provides reusable components picked up by other projects: Laravel itself integrates several of them, and so does Drupal.

Old by reputation, current in practice

PHP’s image is still often that of a 2000s-era language, good at best for running a blog. The numbers tell a different story: it remains by far the most widely used server-side technology, and version 8 brought a JIT compiler and a much stricter type system than its origins would suggest: the usage numbers describe a language quite different from the one its reputation suggests.