A free, browser-based tool for generating and exporting Sudoku puzzle books. Pick a difficulty, set a count, preview every puzzle, then export a KDP-ready 6×9” PDF: cover, intro, all puzzles, and a full answer key. No account required. No server. The entire engine runs in your browser.
The Problem
KDP is an obvious revenue channel for puzzle books. The problem is the toolchain. Dedicated Sudoku generation software costs money and exports generic-looking books. Custom design in Adobe InDesign is slow. Hiring someone to generate 200 unique, verified puzzles for each book isn’t repeatable.
We wanted a tool that generated unique, seed-reproducible puzzles, rendered them beautifully, and exported a print-ready file, all without leaving the browser. So we built it.
How It Works
The puzzle engine uses a seeded Mulberry32 RNG. Every puzzle is generated from a combination of a base seed and a per-puzzle offset, which means any book can be reproduced exactly by saving the seed. The solver verifies unique solutions. No ambiguous puzzles ship.
The export engine uses jsPDF to construct the full book client-side:
- Cover page: Title, subtitle, sample puzzle preview, edition banner.
- Intro page: How-to-play rules, screen detox copy, your website URL.
- Puzzle pages: One puzzle per page, KDP 6×9” with 0.125” bleed, Risograph two-color palette (forest green + coral).
- Answer key: 6 mini-grids per page at the back.
The Risograph visual style is baked into the PDF renderer: alternating box shading, duotone grain, thick box borders, coral number shadows. Every export looks finished without any design work.
Configuration
| Setting | Options |
|---|---|
| Difficulty | Hard (~24 clues), Expert (~20 clues), Mixed (alternating) |
| Puzzle Count | 10–200 in increments of 10 |
| Book Title | Custom (appears on cover and back page) |
| Subtitle / Series | Custom (appears on cover band) |
| Website URL | Printed in intro and back matter |
| Book Seed | Manual or randomized, hex value, fully reproducible |
Revenue Model
A tip modal appears before the main PDF export. Users can send a tip via Stripe Payment Link before downloading, or skip and export anyway. The answers-only export skips the modal entirely. No friction on utility use. The tool is free. The tip is optional.
Stack
| Tool | Role |
|---|---|
| Vanilla JS | No build step, no framework, no npm |
| jsPDF (CDN) | Client-side PDF generation: full book assembled in-browser |
| Cloudflare Pages | Hosted inside the Wanessa Labs Games hub |
KDP print specs baked into the renderer: 6×9 inches, 0.125-inch bleed, 0.75–0.875-inch safe margins.