As of 2014, the website Simple Sudoku offers free software to create sudoku puzzles for the Windows 9X, 2000, and XP operating systems. Angus Johnson developed the program in 2005, and it was last copywritten in 2007. The software is intended for private use only.
The puzzles at Simple Sudoku come in five difficulty levels that range from easy to extreme. Puzzles are generated randomly, which almost guarantees that players will never see the same puzzle twice. The program provides players with helpful tools, including logical hints and the option to undo and redo moves. Players can also save games and start puzzles over with tips on how to begin. The site can be viewed in English, French, Spanish, German and Russian.