Enabling Open Innovation & Collaboration | The Eclipse Foundation | Free
The Eclipse Foundation – home to a global community, the Eclipse IDE, Jakarta EE and over 350 open source projects, including runtimes, tools and frameworks.

Eclipse PHP Development Tools | The Eclipse Foundation | Free
The PHP IDE project delivers a PHP Integrated Development Environment framework for the Eclipse platform. This project encompasses the development components necessary to develop PHP-based Web Applications and facilitates extensibility. It leverages the existing Web Tools Project in providing developers with PHP capabilities.

Welcome to NetBeans | Free
Quickly and easily develop desktop, mobile, and web applications with Java, JavaScript, HTML5, PHP, C/C++ and more. Apache NetBeans IDE is free and open source and is governed by the Apache Software Foundation.

Aptana Studio | Free
The world’s most powerful open-source web development IDE just got better. Rebuilt from the ground-up. It’s now much faster, customizable and includes new features to help you be more productive.

CodeLite • Open Source, Cross Platform C,C++,PHP and Node.js IDE | Free
CodeLite is an open source, free, cross platform IDE specialized in C, C++, PHP and JavaScript (mainly for backend developers using Node.js) programming languages which runs best on all major Platforms (OSX, Windows and Linux).

A cross-platform IDE for C, C++, Python, QML/JavaScript and PHP | KDevelop | Free
Built on modern open source technology, the KDevelop IDE offers a seamless development environment to programmers that work on projects of any size. It helps you get the job done while staying out of your way.

PHP Tools for Visual Studio – Visual Studio Marketplace | Free
Provides full featured support for editing and debugging PHP programs. PHP Tools for Visual Studio transparently integrate into Microsoft Visual Studio. The extension is focused on developer productivity respecting conventions. It understands the code, provides smart code completion, quick navigation, error checking, code diagnostics, code formatting, integrated PHP manual, project system, debugging support, composer package manager, and more.

PhpStorm: Smart IDE for PHP Programming by JetBrains | Paid
PhpStorm is a perfect PHP IDE for working with Symfony, Laravel, Drupal, WordPress, Zend Framework, Magento, Joomla!, CakePHP, Yii, and other frameworks. Lightning-smart PHP IDE US $199.00 /user 1st year. US $159.00 /2nd year. US $119.00 /3rd year onwards.

NuSphere PhpED – Complete PHP IDE for PHP Development | Paid
PhpED – PHP IDE integrated development environment for developing web sites using PHP, HTML, Perl, JScript and CSS that combines a comfortable editor, debugger, profiler with the MySQl, PostrgeSQL database support based on easy wizards and tutorials.Easy to use for debugging PHP scripts, publishing projects to remote servers through FTP, WebDAV, CVS. It is suitable for multiple developers and very large projects. Working with SOAP servers. PhpED 19.2 Professional for Windows support PHP 7.4 / $179.00.

Zend Studio PHP IDE | Zend by Perforce | Paid
Zend Studio is your proven PHP IDE, that can be used as a standalone solution or used with Zend Server as a wholly integrated solution. Zend Studio Commercial Perpetual License for professional developers and businesses / $189.00.

Komodo IDE | ActiveState | Paid
One IDE for All Your Languages. Code faster with the IDE for today’s web languages – Python, PHP, Perl, Golang, Ruby and more. For Windows, Mac and Linux. (Coder) 1 User $7/mo. (Team) 4 Users $76/mo + Technical Support.