Randoku

Randoku: Free Open-Source Sudoku Puzzle Generator

Create randomized, solvable Sudoku boards of varying difficulty levels for printing or game use, with logical validity ensured by constraint programming algorithms.

What is Randoku?

Randoku is an open-source Sudoku puzzle generator written in Python. It uses constraint programming techniques to randomly generate new Sudoku boards that have a unique solution.

Randoku allows users to specify the desired difficulty level, from very easy to extremely hard. It does this by generating puzzles with more or less starting digits revealed. For easy puzzles, many digits are shown in the starting grid. For hard puzzles, very few digits are revealed at the start.

A key benefit of Randoku is that all puzzles it generates are guaranteed to have just one solution. This is accomplished by modeling the Sudoku constraints in code and using a recursive backtracking algorithm to find valid boards. The puzzles are random, yet still solvable.

Randoku is free to use and the source code is available on GitHub under an MIT license. It can generate puzzle PDFs, text files, and images. The puzzles it creates have been used in Sudoku books, apps, websites, and more. It's an easy way to get a virtually unlimited supply of fresh, interesting Sudoku boards.

Randoku Features

Official Links