PHPCodeChecker - PHPCodeChecker is a best-in-class service that enables developers and PHP programmers to write their code online and analyze it.
PHPTester.net - PHPTester.net gives developers and learners the ability to write their PHP code and get the output online.
OnlinePHPFunctions - OnlinePHPFunctions is a powerful online code tester that lets you add PHP source code and view its output on your favorite web browser.
PHPUnit - Application and Data, Build, Test, Deploy, and Testing Frameworks
Paiza.io - Paiza.io allows you to write and run code in many languages.
PHP Sandbox - PHP Sandbox is one of the major online sites that provides a Development Environment for PHP equipped with a Composer Package.