Jeff Widderich had the idea for Str8ts in 2008. Together with Andrew Stuart, he developed a new puzzle that is a successful successor to Sudoku. It is a puzzle where you have to enter the numbers 1 to 9 in the fields, where each digit may occur only once per line and column.
With the app you can daily download new puzzles and solve them for free. There are puzzles in different difficulty levels, so that everyone will find something for their level of knowledge. If you can not find a solution, the integrated solver helps to find the next steps. The integrated solver is able to solve even the most extreme str8ts puzzles with a backtracking algorithm. So far, we've only found two puzzles where the one-step backtracking algorithm did not find a solution and needed support from the user.
As a further function, you can even enter puzzles, which are available for example in printed form, by hand. An import via a text format is also possible.
We thank Jeff Widderich and Andrew Stuart, who gave us permission to use the name "Str8ts". A highlight, of course, is the link from Andrew, through which he daily provides us with new puzzles for the app.

What’s New

Version 2.0

With the update to iOS 13, a function was implemented that can be used to scan Str8ts puzzles from printed templates using the camera.
A rare problem with the automatic Str8ts solver has also been fixed.

App Privacy

The developer, Th. Wolf, has not provided details about its privacy practices and handling of data to Apple. For more information, see the developer's privacy policy.

No Details Provided

The developer will be required to provide privacy details when they submit their next app update.


Th. Wolf
1.4 MB

Requires iOS 13.0 or later. Compatible with iPhone, iPad, and iPod touch.


English, German

Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

More By This Developer

You May Also Like