MarApp Sudoku

Full list of features

• Multiple difficulty levels
  Play Novice or Advanced. Premium opens Expert and Custom levels. The Advanced and Expert levels start with fewer initial digits on the board and require increasingly more advanced techniques to solve the sudoku.
• Clean, modern design
  A carefully tuned interface with smooth animations and no visual clutter.
• Manual notes mode
  Add and remove candidate notes yourself for full control and classic Sudoku play.
• Live candidate updates
  Notes are kept consistent and up to date as you place or undo numbers.
• Show & hide notes instantly
  Toggle note visibility from the app bar without deleting them. This is particularly useful when you have lots of candidate notes and want a clutter free view of the board for a moment.
• Highlighting tools (optional)
  Highlight the selected row & column, sub-grid, matching digits in cells, matching digits in notes and affected (blocked) cells for a digit — all individually configurable.
• Mistake prevention – collisions (optional)
  Optional checking to prevent placement of a colliding digit (placing the same digit in the same row, column or sub-grid as an existing digit). If “Allow digit conflicts” is set to off, placing the digit will fail and colliding digits are highlighted.
• Mistake prevention – other mistakes (optional)
  Optional additional error checking prevents not so obvious illegal moves and helps avoid frustration caused by an earlier placed digit blocking a valid solution of the game in the end.
• Undo & erase
  Freely undo moves or erase entries, including notes.
• Validate
  Check to see whether the board is still valid.
• Adaptive interface
  When you have placed all nine instances of a digit on the board, the button for this digit is muted. The Notes tool-button changes to remind you that manual notes or auto-notes (Premium feature) is turned on.
• Progress timer
  Track your solving time with a clean, compact timer display.
• Best scores & rankings
  Compete against yourself or friends (on the same phone) with best times per difficulty level. Assisted (auto-notes) and non-assisted rounds are clearly distinguished.
• Challenge a friend (optional)
  When you finish a game, you are given the opportunity to challenge a friend. If you choose to do this, you can send your friend a message through your medium of choice (sms, email, WhatsApp, etc.) which contains a code that can be imported into MarApp Sudoku on their phone or tablet to play the same game as you did. With Premium, received challenges can be saved to Sudoku Library, where you can add a note about who sent them and play them later. But watch out! Maybe you get a challenge in return… 😅
• Import a game
  The import function lets you easily import a game in standard sudoku format (a sequence of 81 digits that represent the initial digits of the game). The import function also accepts a special MarApp Sudoku code you may get as part of a Sudoku Challenge from a friend. You may paste the entire message from the challenge or just the MarApp Sudoku code in the import page. With Premium, imported challenges can also be saved directly to Sudoku Library, so you can keep track of them and play them when it suits you.
• Highly configurable
  Settings allow you to configure MarApp Sudoku as you like it. For example, you may turn on or off all highlight tools individually.
• Fully offline
  No internet connection required — play anytime, anywhere.

Premium 👑 features

With Premium you get everything in features above, plus:

• Extra difficulty levels
  Play Expert and Custom (create your own puzzles) levels, in addition to Novice and Advanced.
• Custom themes & appearance
  Choose from multiple themes with individual backgrounds and visual styles to match your mood, preference and lighting conditions. Whether you go for a calm «Balance», go wild with «Rainbow Falls» or prefer «Midnight Manor» is entirely your choice.
• Safe ground
  Takes the board back to the last valid state (both digits and notes, but notes are not validated specifically). Gives you a fresh start if you suspect you have placed one or more numbers incorrectly earlier in the game.
• Smart auto-notes (optional)
  Automatically fills in and updates candidate notes using logical deduction techniques. When enabled, the round is clearly marked as Assisted in best scores.
• Surrender & step-by-step reveal (optional)
  If you get stuck, reveal the solution gradually with logical explanations. When you click the «Surrender flag» in the app bar, this starts a step-by-step walkthrough of the remaining solution of the sudoku board, with highlights in the board as well as text telling you why the solution is valid for each step. This is intended as a tutoring function, to help you improve your sudoku skills and help you master Sudoku.
• Sudoku Library
  Build your own personal Sudoku Library. Save favorite puzzles, organize challenges, add notes, mark favorites, replay puzzles later, and track your best time for each saved puzzle.
• Advanced logical reductions
  Auto-notes and Surrender use techniques such as naked single, hidden single, naked pair, hidden pair, naked triple, hidden triple, box-line reduction (pointing pair and pointing triple), X-Wing, Swordfish and XY-Wing to reduce candidates safely and efficiently.
• Unlimited games
  Play as many games as you desire (the free version is limited to 10 new games per week).

• No ads — ever
  Ads may be added to the free version later, but never in the Premium version.

Accessibility features

• For left- & right-handed
  Left- and right-handed layouts ensure the game works well for everyone.
• Adjustable digit size
  You may choose between three digit sizes for the game-board.
• Light or dark mode
  The colours are adjusted to go well with the individual themes, but you may choose between light or dark mode for the game-board.

User Safety & Privacy

• No account required
  Play immediately without creating an account or sharing personal information.
• No data collection or tracking
  MarApp Sudoku does not collect, track, or sell user data.
• Fully offline gameplay
  All puzzles, progress, and scores are stored locally on your device.
• No ads, no third-party trackers
  The app contains no advertising SDKs or analytics trackers that monitor user behavior.
• Transparent assisted play
  When assistance features such as auto-notes are used, the round is clearly marked as Assisted — ensuring honest scoring and fair comparisons.
• Safe for all ages
  No social features, messaging, or external links (other than clearly marked links pointing to information on this website) — making the app suitable for children and families.
• Minimal permissions
  MarApp Sudoku only uses system permissions that are strictly necessary for core functionality.
• Your data stays yours
  Game progress, settings, scores, and saved library puzzles never leave your device.