---
title: Install the PHP SDK
slug: feature-experimentation/docs/install-sdk-php
docTags: 
createdAt: 2026-08-05T20:39:57.000Z
---

The Optimizely Feature Experimentation PHP SDK is available through [Composer](https://getcomposer.org/).

SDK version 4.0.0+ requires PHP 8+.
SDK version 3.0.0+ requires PHP 5.5+ up to PHP 7.

To install using Composer:

```shell
composer require optimizely/optimizely-sdk
```

The full source code is available on [GitHub](https://github.com/optimizely/php-sdk).