I've just put the finishing touches on my Sudoku program, after over a year of development.
Sue is meant primarily as a helpful interface for entering and solving Sudoku puzzles (and for learning some of the solving techniques). But it also is a puzzle generator and solver. It includes a Guided Solve process, Hints, narrated tutorials, and score tracking.
I wrote it while I was learning Sudoku, as an aid for myself, but then polished it up and added features so that others who were learning might also find it helpful. I've always found that the best way for me to learn something is to try to imagine how I would teach it to someone else.
It is written entirely in Javascript (with a PHP back-end to access its database), so there is nothing to download.
Please visit https://smmcroberts.net/sudoku/ and take a look.
There is a video tutorial which shows all of the features of the site, and explains how to use them. This is available on the site, under the Tutorials tab, or you can go directly to the video at: https://smmcroberts.net/sudoku/doc/sueintrov2hb.mp4