Komodo Edit is a free, open source, multi-platform, multi-language editor for dynamic languages and Ajax technology, including Perl, PHP, Python, Ruby and Tcl; plus support for browser-side code including JavaScript, CSS, HTML and XML.

Background syntax checking and syntax coloring catch errors immediately, while autocomplete and calltips guide you as you write. Available on Windows, Mac OS X and Linux. XPI extensions allow you to create your own plug-ins. XPI extension support provides the same capability as Firefox, with all standard Mozilla APIs based on XUL, XBL, and XPCOM, plus our own for Python and JavaScript.

Features
Multi-language editor
Advanced support for:
* Browser-side languages: CSS, HTML, JavaScript and XML
* Server-side languages: Perl, PHP, Python, Ruby and Tcl
* Web template languages: RHTML, Template-Toolkit, HTML-Smarty and Django

Autocomplete and calltips
* Write code faster and shorten the learning curve with code completion that guides you as you work
* CSS, HTML, JavaScript, Perl, PHP, Python, Ruby, Tcl, XML and XSLT.
* Schema-based XML/HTML completion
* Multiple-language file support, such as CSS and JavaScript completion in HTML
* Support for adding third-party libraries
* Interpreter version differentiation of built-in and standard library information

Multi-language file support
Correct syntax coloring of multi-language files and templated files, common in many web programming frameworks. Add custom language support (User-Defined Languages or UDL, used to provide support for RHTML, Template-Toolkit, HTML-Mason, Smarty and Django).

Standard editing features
Code commenting, auto-indent and outdent, block selection, incremental search, reflow paragraph, join lines, enter next character as raw literal, repeat next keystroke and clean line endings on "save".

Syntax checking
Instant feedback for all fully-supported languages.

Syntax coloring
Spot errors easily and improve readability and context, even in multi-language files (unique to Komodo!).

Vi emulation
Modal Vi keybindings emulate navigation, text insertion and command behavior. Custom commands can be implemented by adding Komodo macros to a Vi Commands Toolbox folder.

Emacs keybindings
Emacs-like keybinding scheme supports new editor features modeled on Emacs, such as transient marks (similar to the Emacs "mark ring"), repeat next command and reflow paragraph.