Kodiak PHP - Kodiak PHP can run any PHP code directly (offline) on your iPad, no need for an internet connection.
Google App Engine - A powerful platform to build web and mobile apps that scale automatically.
CodeLobster PHP Edition - CodeLobster - Free portable PHP IDE with support Drupal, Smarty, Twig, WordPress, Joomla, JQuery, CodeIgniter, HTML, CSS, JavaScript, AngularJS, CakePHP, Facebook, Laravel, Phalcon, Symfony, Yii
Dokku - Docker powered mini-Heroku in around 100 lines of Bash
Rapid PHP - Rapid PHP editor is the world's fastest and lightest PHP IDE for Windows with code intelligence and tools for PHP, HTML, CSS, and JavaScript, including PHP debugger, FTP/SFTP client, UTF-8 support and more.
Google Cloud Functions - A serverless platform for building event-based microservices.