About Sudoku App
We built Sudoku App because we were tired of the ads. Every major Sudoku site seemed to prioritize ad impressions over puzzle quality — auto-playing videos, full-screen interstitials, and bloated page loads that made solving feel like an afterthought. We thought there should be a better way.
What We Believe
Sudoku is a pure, elegant puzzle. It doesn't need gamification gimmicks, microtransaction currency, or a social feed. It needs a fast-loading grid, a reliable engine that generates genuinely well-formed puzzles, and features — like smart hints — that actually help you become a better solver rather than just feeding you answers.
That's what we built. Six difficulty levels, from Easy to Extreme, with a solver engine that generates verified unique-solution puzzles and a hint system that shows you the reasoning, not just the result.
The Engine
Our Sudoku engine is written in TypeScript and includes a backtracking solver, a constraint-satisfaction generator, a difficulty grader, and a hint engine that recognizes nine distinct solving techniques — from naked singles and hidden pairs up to X-wings and swordfish patterns. Every puzzle you play has been programmatically verified to have exactly one solution before it reaches your screen.
Free, Always
All puzzles on Sudoku App are free to play, no account required. Your game progress saves locally in your browser — we don't track it on our servers. We may introduce a single, non-intrusive ad unit in the future to cover hosting costs, but we will never use pop-ups, video ads, or any format that interrupts your solving experience.