CharGrid is a fast, offline-first native puzzle app for iPhone and iPad. Its first game is Sudoku, designed around immediate touch, keyboard and Apple Pencil input without advertising, interruptions or dark patterns.

The SwiftUI interface is backed by a dedicated Rust engine that generates valid puzzles, checks solutions and stores progress locally through SQLite. Optional assistance, appearance controls, offline puzzle sharing, iCloud support and honest Game Center leaderboards create a polished experience that remains quiet and focused on play.

The architecture establishes a reusable home for grid puzzles, keeping platform-native interaction separate from the rules and persistence engine so both can evolve cleanly.

Defined the product principles, interaction model and roadmap, deliberately rejecting advertising and engagement dark patterns in favor of calm, intentional play.

Designed and built the native iPhone and iPad experience, including touch, keyboard and natural Apple Pencil input.

Engineered a reusable Swift and Rust architecture with local SQLite persistence, puzzle generation, validation, sharing, iCloud support and Game Center integration.

Created a paper-like way to solve Sudoku on touch devices while retaining the speed and assistance of a native application.

Established an extensible engine for future grid-based games without coupling game rules to platform-specific interaction.

Product Strategy

Native App Design

Swift Development

Rust Development