PHPCI is a continuous integration tool specifically tailored for PHP projects. It automates the process of testing PHP code every time a new commit is made, ensuring that any integration issues are identified quickly and efficiently. PHPCI supports various PHP testing tools like PHPUnit, PHP Spec, and Behat, making it a versatile choice for PHP developers looking to maintain high standards of code quality. The platform is open-source, allowing for customization and enhancement by the community.