shhdoku.org

Sudoku with nothing on the board but the puzzle. A Svelte page that builds a board in your browser and proves it has one solution, with twenty-five rulesets, daily challenges and no ads.

Open shhdoku.org · All projects

Type: Text and Grid Engine / Single Page Application (SPA)
Domain: Logic / Puzzles

Purpose & Origins

shhdoku.org started with a friend complaining about the state of digital puzzle games. Most mainstream mobile and web Sudoku apps have turned into carriers for full-screen video ads, subscriptions you are pushed into, heavy telemetry, and notification pings. The aim was to strip all of that out and leave a board with nothing on it but the puzzle. I reject this reality and substitute my own.

Architecture & Technology

shhdoku.org is a single page built with Svelte and compiled down to plain JavaScript, with no runtime dependencies. It generates a solved grid, removes clues until the board matches the difficulty tier you asked for, and proves the result has exactly one solution, all in your browser. The generator uses exact-cover backtracking (Dancing Links) and a seeded random number generator, running in a Web Worker so the page never stalls, and the same seed always gives the same board: a new puzzle appears instantly without contacting a server, and a printed puzzle code recreates it anywhere. The game in progress lives in localStorage and your play history in IndexedDB, both only on your machine, with a backup file you can export, so a session carries on offline with nothing to wait for on the network.

Scope & Uniqueness

Most puzzle apps are built around advertising. shhdoku.org is built around restraint. It works offline as an installable progressive web app, carries twenty-five rulesets from Killer to Jigsaw behind the same quiet board, and what is left is a board rather than a thing trying to keep you on it.

Screenshots