Windows Setup

On Windows, PHP can run directly in PowerShell, through a local development stack, inside WSL, or inside containers. The important skill is proving which runtime your project is using.

Windows PHP setup problems usually come from PATH order, multiple PHP installs, missing DLL extensions, wrong php.ini, or mixing Windows PHP with WSL PHP without realising they are separate environments.

Common Windows PHP Setups

Typical options include:

• official PHP ZIP builds
• XAMPP, Laragon, WampServer, or similar stacks
• Herd or other modern local development apps
• WSL with Linux PHP
• Docker Desktop containers

Any of these can work. The professional habit is recording which one the project expects and then proving the active PHP runtime.

Find The Active PHP Binary

In PowerShell:

where php
php -v

Example output:

C:\php\php.exe
PHP 8.3.12 (cli)

If where php prints several paths, Windows will use the first one found on PATH. That first result is the one php runs from the terminal.

If php -v fails, PHP is either not installed, not on PATH, or the terminal session has not picked up the updated PATH yet.

PATH On Windows

PATH is the list of directories Windows searches when you type php.

You can inspect it in PowerShell:

$env:Path -split ';'

After changing PATH through Windows settings or an installer, close and reopen PowerShell. Existing terminals may not see the update.

Avoid leaving old PHP installs earlier on PATH. That is how a project accidentally runs C:\xampp\php\php.exe when you expected C:\php\php.exe.

php.ini And Extensions

Check the loaded configuration:

php --ini

Check extensions:

php -m
php -m | Select-String mbstring

Important Windows-specific detail: many extensions are DLL files loaded from extension_dir.

Check the configured extension directory:

php -i | Select-String "extension_dir"

If extension_dir points at the wrong folder, PHP may not load extensions even when the .dll files exist somewhere else.

Inside PHP:

<?php

declare(strict_types=1);

echo 'Loaded ini: ' . (php_ini_loaded_file() ?: 'none') . PHP_EOL;
echo 'extension_dir: ' . ini_get('extension_dir') . PHP_EOL;

foreach (['mbstring', 'pdo', 'openssl'] as $extension) {
    echo $extension . ': ';
    echo extension_loaded($extension) ? 'loaded' : 'missing';
    echo PHP_EOL;
}

// Prints:
// Loaded ini: C:\php\php.ini
// extension_dir: ext
// mbstring: loaded
// pdo: loaded
// openssl: loaded

Composer On Windows

Composer uses a PHP runtime too. Check both:

php -v
composer --version
composer check-platform-reqs

If Composer reports missing extensions, do not immediately edit application code. First confirm:

• which php.exe is active
• which php.ini is loaded
• whether the extension is enabled
• whether extension_dir points at the correct DLL folder

Windows PHP And WSL Are Separate

Windows PHP and WSL PHP are different runtimes.

PowerShell:

where php
php -v

WSL shell:

which php
php -v

Those commands can show different PHP versions, extensions, configuration files, and filesystem paths.

If a project runs inside WSL, install and verify PHP inside WSL. If it runs in PowerShell or a Windows stack, verify Windows PHP. Mixing the two is a common source of confusion.

Run A First Script

Create hello.php:

<?php

declare(strict_types=1);

echo 'Hello from PHP ' . PHP_VERSION . PHP_EOL;

// Prints:
// Hello from PHP 8.3.12

Run it:

php hello.php
php -l hello.php

Run A Local Web Request

Create public/index.php:

<?php

declare(strict_types=1);

header('Content-Type: text/plain');

echo 'Hello over HTTP' . PHP_EOL;
echo 'SAPI: ' . PHP_SAPI . PHP_EOL;

// Browser output:
// Hello over HTTP
// SAPI: cli-server

Start the built-in server:

php -S 127.0.0.1:8000 -t public

Open:

http://127.0.0.1:8000/

This proves Windows CLI PHP can serve a local request. It does not prove IIS, Apache, Nginx, WSL, or Docker are configured.

Windows Setup Checklist

For a project setup note, record:

1. Whether the project uses Windows PHP, WSL, Docker, or a dev stack.
2. What where php returns.
3. What php -v returns.
4. What php --ini returns.
5. What extension_dir is set to.
6. Which extensions the project requires.
7. Whether composer check-platform-reqs passes.
8. How to run the local server.

This gives the next developer a way to prove their environment instead of guessing.

What You Should Be Able To Do

After this lesson, you should be able to find the active PHP binary on Windows, inspect PATH, check php.ini, verify extension_dir, check loaded extensions, understand the Windows/WSL boundary, and run a basic PHP script and local server.

For junior PHP work, this matters because Windows can have several PHP runtimes installed at once. The useful skill is identifying the one your project is actually using.