Hi HN, I've been working on this Sudoku web app for the past couple of years, on and off during free weekends and afternoons. I started working on it because I was bored during COVID, and Cracking the Cryptic had just become popular on YouTube, which got me wondering how hard it could be to make a Sudoku app. The main idea is for the app to understand the constraints and know how to solve Sudoku grids (and not just be a simple Sudoku drawing/playing app). When it comes to classic Sudoku, the solver doesn't support anything more complicated than X-Wing, but it understands the constraints.<p>At the moment, most of the popular variants are supported: killer, sandwich, arrow, thermo, palindrome, German whisper, kropki, consecutive, non-consecutive, greater than, XV, diagonal, anti-king, anti-knight, even-odd, windoku, renban, and zipper. The only variant I am yet to add support for is quadruple. If any other variant becomes popular, I will probably add it, as was the case with zipper lines during development.<p>A user account is not required to play, but it is required if you want to publish a public grid on the app. The app doesn't collect any PII, doesn't have ads or trackers. Accounts are identified by email hash; I am not storing email addresses or passwords, and OTPs are sent by email. The less I know about users, the better for both sides.<p>The app supports mobile devices, but it works best on bigger screens. It was built using Blazor SSR/WASM (AOT) with SVG for interactive parts. I know there are some performance issues (especially on mobile phones and with touch input), and I am trying to address them.<p>Some of the features I was thinking about adding are classifying grids by difficulty, daily Sudoku, and maybe campaigns (groups of Sudoku grids where users have to solve them in order).<p>If you like Sudoku, or more specifically variants of Sudoku, please let me know what you think about SudokuVariants.<p>URL: <a href="https://sudokuvariants.com" rel="nofollow">https://sudokuvariants.com</a><p>Thanks!