Best Free Tools for Programmers

Tools for any programming language and specialized tools, in the list of languages below...

Programming languages AspectJ - Basic - C - CIL - C++ - C++11 - C# - Dart - Eiffel - Go - Java - JavaScript - JavaFX Script - Pascal - PHP - Python - QML - Rexx - Ruby - Scala - Scriptol - Tcl - HTML - XML - XAML - XUL - SQL

IDE & RAD (Integrated & Rapid Application Development)
NetBeans IDE for several languages including Java and PHP with a built-in server. (Java)
Maqetta HTML 5 online WYSIWYG authoring tool by IBM. The source is available to be uploaded on a server.
May be used locally once started the embedded server.
Eclipse Multi-languages IDE to integrate various programming tools. You can add other tools. (Java)
Ideone Interactive online tool that allows testing (compile/interpret) source code in 40 programming languages and display the result.

Graphical User Interfaces for Cross-platform Programs
XAML Markup language for user interfaces design. Used by the Metro interface of Windows 8 for immersive applications and by the Silverlight plugin.
Gtk+ GUI widely used for applications. (Win/Lin).
SDL A library for game programming using all resources (sound, video, devices) of the computer, for any language, any OS. Use OpenGL, DirectX. (Win/Lin).
Qt Cross-platform user interface framework, inclusing mobiles. LGPL license. (Win/Lin/Mac/Mobiles).
An IDE, QtCreator is provided to build applications.

Utilities for releasing a software
Inno Setup Complete installer, can add your program on the desktop, provides an uninstaller for your program, into the archive that is bigger than those of above. Open source.
IZarc Archive manager. Can build, extract, convert ZIP, BZ2, TAR, GZ, CAB archives and the new 7z format. Manages also CD images
See the list of free archivers.
Doxygen Produces a HTML/Latex/XML/Man documentation from source files.
UPX Compresses binary executables and shrink them up to 30%.(Win/Lin)

Graphical and Sound Tools
Paint.NET Drawing program similar to Photoshop, easier to use than Gimp. Supports layers and a lot of filters. Has graph tools. (Win).
Paint.NET here.
XnView Image viewer and manager, recognize almost any format plus video ones: Mpeg, Divx (Win/Lin)
Inkscape Vectorial graphical editor allowing to make SVG files (Win/Lin).
MWSnap Screen capture. Delimits a windows or a region.(Win)
Slate Video builder : make your own videos quickly in a comic style.
Terragen Landscape editor with photographic quality.
Graphics : Expert level
Gimp Drawing program, open source replacement for Photoshop. Despite that it is bugged under Windows has interesting features. The filters provide tools for sophisticated image processing. (Windows / Linux)
Visualization Toolkit 3d visualization tool, open source. (Win/Lin).
POV Most powerful 3D ray tracer. Programming skill required. (Win/Lin)
Open FX 3D image maker.
More graphic tools.

Web and HTML 5 tools
TidyHtml Test HTML page for malformed code.
Wordpress Tool to help in creating a blog or even any website. (PHP and MySQL)
Anaa Small Ajax and Gears framework with the main functions: load XML, text or HTML contents, post a text or command to the server.
Link Checker Check a website for broken links. (PHP). See also Xenu's link (Win)
List of CMS Modern big websites are built with a CMS (Content Management System) as Joomla, Drupal, Xoops for portails, phpBB or punBB for forums, Wordpress for blogs.
PHP The PHP interpreter and the tutorial. More tools for PHP on the card.

Editors (Text, HTML, XML)
Kompozer Wysiwyg HTML editor. (Win/Lin/Mac).
Amaya HTML editor and browser of the W2C, compatible with the standards. (Win/Lin/Mac).
PSPad Complete editor for any programming languages including HTML and XML. Internet features. Several foreign languages supported. (Win).
Geany Cross-platform tabbed code editor. Extensible with plugins.
Pandoc Convert documents between different markup formats.

LibreOffice

Perfect to write manuals with images, supports HTML and PDF. (Win/Lin/Mac).
More tools and infos on the HTML card. Languages may have specialized editors also.

Web Tools and Online Services
Filezilla Upload files on the net. (Win).
For updating a website from local files, the command line FTP synchronizer is well suited.
Page Test Check your web pages for validity, according to the HTML 4 standard. You can check also XML and CSS.
Browser Test Check your home page with several browsers and display it on the site for some times.
Webmaster Tools Google's service, reports backlinks to each page, keywords of search to the webmaster of the site only.
Bioloide Online interface with various tools to check a website. Extensible by adding new tabs from the setup panel.
Includes the Ara online RSS editor, to build and edit the feed of your site.
Requires PHP 5.
Google's tools List of tools and services for webmasters..

Tools for SQL Databases
Kexi Database designer. (Win/Lin).
Xampp or Wamp Local server with MySQL and user interfaces to databases. (Win)

Other Tools
Unix Tools Windows version of all Unix tools. (Win)

Documentations and Tutorials
HTML - XML Lot of tutorials about HTML, XML, etc... ont the W3 consortium site.
Thinking C++ C++ tutorial with exercices.
OpenGL All Open GL tutorials.
OpenGL Lessons Complete tutorial on OpenGL with examples and sources for each compiler.
Wotsit Formats of files, sources and other resources for programmers.
DaFont Fonts and tools.
See at each programming language on top of this page for specific tutorials.
Labels:  Win)dows,Lin)ux, Mac)Intosh, Java or PHP: all OS, Nothing: Windows

Technical tools and documentation