Sudomoji

Inspiration

Sudomoji was — a spontaneous idea to create a fun, community-driven logic game entirely inside Reddit. I wanted to see how far I could push Reddit’s new interactive post capabilities by turning something familiar, like Sudoku, into a collaborative challenge for redditors. With Kiro powering our workflow, we built quickly, experimented freely, and let creativity guide structure — proving that with the right tools and community spirit, even a casual idea can evolve into something playful and polished.

What it does

Sudomoji transforms classic Sudoku into a community-powered Reddit game that lives entirely inside interactive posts. Players can solve puzzles, climb leaderboards, and even create their own Sudomojis using custom emoji sets — making each puzzle unique to the creator’s imagination. Every post becomes a shared playground where redditors compete, comment, and celebrate their logic skills together. It’s Sudoku reimagined for Reddit — social, creative, and built for the community.

How we built it

Sudomoji was built entirely using Kiro — from generating hooks and specs to testing and deploying inside Reddit’s Devvit Web environment. Every piece of logic, from the Sudoku generator to the leaderboard engine, was created, validated, and iterated using Kiro’s tools in a pure vibe coding flow. We used Kiro Hooks to manage puzzle states, Kiro Specs to define Sudoku logic and community interactions, and Kiro Steering to quickly wire up leaderboards and player submissions without manual setup. The result is a polished, Reddit-native community game built purely through Kiro’s ecosystem — fast, modular, and powered by creativity.

Challenges we ran into

This was my first time building on Reddit, so understanding how interactive posts, permissions, and subreddit setups worked took some trial and error. At times, my explanations or logic for certain game flows weren’t clear enough — which meant redoing and refining parts of the system multiple times until it felt smooth and intuitive. Since Sudomoji was built entirely through vibe coding in Kiro, finding the right structure while staying in flow was also tricky. I had to balance creativity with clarity — rebuilding sections until the logic, UI, and Kiro hooks aligned perfectly. Each iteration, though, made the game stronger and cleaner.

Accomplishments that we're proud of

We’re proud that Sudomoji was built completely from scratch in just four days using Kiro and Devvit Web. It was my first time building on Reddit, yet I managed to create a fully functional, community-driven game with a custom Sudoku logic engine, leaderboard system, and support for user-created puzzles. Despite the short timeline and learning curve, the project reached a polished, Reddit-native experience through pure vibe coding, iteration, and creativity.

What we learned

Building Sudomoji taught me how powerful Reddit’s new Developer Platform can be when paired with the right tools. It was my first time developing on Reddit, and I learned how interactive posts, permissions, and data flow actually work in practice. Using Kiro throughout the process showed me how fast and structured vibe coding can become when supported by automation. I also learned the value of explaining my logic clearly and reworking flows until everything feels natural — a reminder that iteration is what turns a fun idea into a finished experience.

What's next for Sudomoji

Next, I plan to open Sudomoji to the public by launching it on a dedicated subreddit where anyone can play, create, and share puzzles. The goal is to expand community involvement by allowing redditors to host their own Sudomoji challenges, each with unique emoji themes and leaderboards. I also plan to introduce daily puzzles, multiplayer modes, and more advanced puzzle logic generated dynamically through Kiro. Over time, Sudomoji will evolve from a hackathon experiment into a living community game that grows with Reddit itself.

Built With

• devvit
• kiro
• reddit