About CodeDoku

CodeDoku is a logic puzzle where you fill a 3×3 grid using intersecting clues from rows and columns.

Each cell must satisfy both its row clue and its column clue at the same time. The correct answer is where both constraints overlap.

Puzzles use themes like Animals, Countries, and Food. The name CodeDoku comes from “cracking a code”: deducing each intersection instead of memorizing answers.

One puzzle a day, generated, validated, and shared by everyone. Same board, same challenge, whether you play at breakfast or before bed. When you want more, More Puzzles is always available.

• Tap a cell, choose the concept that fits, and submit one move at a time.
• You start with 5 lives. Only wrong answers cost a life.
• Correct answers turn green and can be cleared to reorganize the board; wrong ones stay open so you can try again.
• Your progress is saved automatically. Leave and come back anytime.

As a software engineer, I wanted to ship a game of my own, not a demo hidden in a repo, but something real people could open and enjoy.

CodeDoku started as an attempt to gamify learning technical concepts. The puzzle mechanics were fun, but the study layer was dull, and that undermined the gamification. I kept the puzzle, removed the learning obligation, and opened the game to anyone.

Watching my wife play daily puzzles brought back the feeling of opening the paper and solving the morning crossword. I wanted that same rhythm in digital form: show up, think, finish, or come back tomorrow, without pressure or performance.

CodeDoku is an indie project that evolves release by release. It's intentionally small, and honest about where it is headed.

There is no fixed public roadmap yet. The project is still evolving as it grows.

If you want to see what's actually been shipped, the changelog has the full list: new animals, UX improvements, daily mode refinements, and everything in between.

View the changelog →

I'm Fernando Bittencourt, a Brazilian software engineer with a degree in Computer Engineering and a postgraduate degree in Distributed Software Architecture. I've spent more than ten years in tech as a software engineer and hands-on tech lead, building systems in production and sketching side projects in parallel.

CodeDoku is where those two worlds meet: engineering discipline and the joy of building something people actually play.

Outside of work, I spend time with my wife, friends, and our Shiba Inu. I enjoy movies, the beach, traveling when possible, and meeting new people and cultures.

LinkedInGitHub

Although CodeDoku is a project I conceive, build, and operate on my own, many people have contributed feedback, suggestions, and testing throughout its evolution. In particular, one person has been actively involved:

Carolinne Melo contributes with data curation, testing, and product feedback. A Statistics student in her final year, she is building a career in Data, BI, and Analytics.

She takes part in creating, reviewing, and validating datasets, identifies inconsistencies and ambiguities in categories and concepts, tests new features and mechanics, and provides ongoing feedback on user experience and rule clarity.

She also participates in discussions about the product's evolution, helping validate ideas, refine concepts, and maintain the quality of content that reaches the game.

Carolinne's LinkedIn

I read every message. The best way to reach me is below.

contact@codedoku.app

Good reasons to write:

• Something broke. Tell me what you saw and what you expected.
• A hint felt unfair or confusing. Help me improve clarity.
• Ideas for future themes (sports, cities, history, anything).
• Feature requests — quality-of-life, new modes, accessibility improvements.
• You solved today's puzzle and just wanted to say hi.