Hi Product Hunt! I built GridLab because I wanted a tool that didn't exist: an app that helps you design Sudoku puzzles for manual solving, not one that walks you through solving them on screen. The idea came from a simple observation: creating a puzzle is harder and more interesting than solving one. When you set the constraints and generate a grid, you have to understand what makes a Sudoku tight, elegant, or broken. The app surfaces the structural properties of each puzzle so you can make informed choices rather than just accepting whatever gets generated. A few things I'm happy with: 5 combinable variants (X-Sudoku, Anti-King, Anti-Knight, Hyper) that stack and interact in non-obvious ways EPUB export so you can load a whole collection onto a Kobo or e-ink device Zero gamification. No badges, no streaks, no levels. The app gets out of your way. Built natively for iPad in SwiftUI, with CloudKit sync. Happy to answer questions from anyone into puzzle design, paper solving, or apps that don't try to keep you hooked.

GridLab

Design Sudoku puzzles worth solving by hand

Design Sudoku puzzles worth solving by hand