Codiad!

Brackets is an open-source editor for web design and development built on top of web technologies such as HTML, CSS and JavaScript. The project was created and is maintained by Adobe, and is released under an MIT License.

A free, open-source Integrated Development Environment for software developers. You get all the tools you need to create professional desktop, enterprise, web, and mobile applications with the Java language, C/C++, and even dynamic languages such as PHP, JavaScript, Groovy, and Ruby. NetBeans IDE is easy to install and use straight out of the box and runs on many platforms including Windows, Linux, Mac OS X and Solaris.The download section conveniently offers prepackaged bundles/installers for each supported programming language containing only required plugins. »

Smart PHP Code Editor

Aptana Studio is a complete web development environment that combines powerful authoring tools with a collection of online hosting and collaboration services that help you and your team do more. Includes support for PHP, CSS, FTP, and more...

Cloud9 is a code editor and development environment built with browser technology yet with the power of a desktop IDE. It's available both as an online service and as a locally hosted platform.

Qt Creator is a cross-platform C++, JavaScript and QML integrated development environment which is part of the SDK for the Qt Framework.

Coda is a fast, clean, and powerful text editor with pixel-perfect preview and a built-in way to open and manage your local and remote files. And a dash of SSH too.

UltraEdit is the ideal text, HTML and HEX editor, and an advanced PHP, Perl, Java and JavaScript editor for programmers. An industry-award winner, UltraEdit supports disk-based 64-bit file handling (standard) on 32-bit Windows platforms (Windows 2000 and later).

ideone.com is a... pastebin. But a pastebin like no other on the Internet. More accurate expression would be "online mini IDE and debugging tool".

Codeanywhere is a code editor in a browser with a powerful ftp client integrated, and all popular web formats are supported (HTML, PHP, JavaScript, CSS, and XML).

PythonAnywhere is a Python development and hosting environment that displays in your web browser and runs on cloud servers. The servers are already set up with everything you need: hundreds of useful Python packages and web frameworks are supported out of the box.

Koding is a developer community and cloud development environment where developers come together and code in the browser – with a real development server to run their code. Developers can work, collaborate, write and run apps without jumping through hoops and spending unnecessary money. The Cloud Development Environment

slap is a Sublime-like terminal-based text editor that strives to make editing from the terminal easier. It has: