Online Sudoku is not just another puzzle app. Built on a modern Flutter frontend and .NET microservices backend, it delivers a competitive gaming experience with real-time multiplayer tournaments, an intelligent hint system that teaches you solving strategies, and three distinct Sudoku variants. Play solo with offline-first reliability, challenge friends head-to-head, or compete in elimination bracket championships against players worldwide.
The timeless Sudoku experience. Fill every row, column, and 3x3 box with digits 1-9. Four difficulty levels from Easy to Expert.
Classic rules with an extra twist — both main diagonals must also contain unique digits. A fresh challenge for seasoned players.
Cage-based constraints replace given numbers. Sum the cells in each dotted cage to match its target — no repeats allowed within cages.
Compete in Best of 3 matches or 16-player elimination bracket championships with live opponent progress tracking via SignalR.
A human-like solver guides you step-by-step through solving strategies — naked singles, hidden singles, and more — so you learn as you play.
Add friends, send challenges, and compete on the same puzzle. Compare completion times and climb the social leaderboard.
Fresh puzzles every day across all variants and difficulty levels. Build streaks and earn rewards for consistent play.
Track your personal bests, completion rates, average solve times per difficulty, and rank against the global player base.
Play anywhere without internet. Your progress syncs seamlessly to the cloud when you reconnect — powered by a local SQLite database with outbox pattern.
Compete in real-time against players worldwide. Our SignalR-powered tournament engine ensures sub-second opponent progress updates and fair matchmaking.
Quick competitive matches — solve the same puzzle, fastest time wins each round.
16-player single elimination championships. Win rounds to advance to the Grand Finals.
Best of 3
Your Progress
Opponent
Download Online Sudoku and join thousands of players competing in real-time tournaments worldwide.