Puzzle game
Zip
Draw one unbroken line through every square, hitting the numbered checkpoints in order. Four board sizes, a shared daily challenge and hints that escalate step by step instead of giving the answer away.
- TypeScript
- React Native
- Expo
- Reanimated
- Fastify
- Jest
- Year
- 2026
- Role
- Mobile app development
- Team
- Solo product
(01)The challenge
A puzzle is only fair with exactly one answer — and proving that is an expensive search that could freeze a phone mid-swipe.
(02)The solution
A framework-free TypeScript engine that generates a path, adds checkpoints until a solver proves uniqueness, and runs identically in the Expo app and a Fastify API.
(03)Features
What it does.
Draw to solve
Drag across the grid and backtrack by retracing.
Daily challenge
The date is the seed, so everyone plays the same board.
Four-tier hints
From a solvability check up to a safe rewind.
Level-pack API
Heavy generation runs on the server, away from the UI thread.
(04)Screens
A closer look.
(05)Process
How it came together.
Discover
Understanding the goal: a puzzle is only fair with exactly one answer .
Design
Structure, key screens and the look agreed before any code was written.
Build
Developed with TypeScript, React Native, Expo — fast, responsive and maintainable.
Launch
Tested on real phones and desktops, then deployed to production.
Improve
Fixes, refinements and new features based on how people actually use it.
(06)Under the hood
Highlights
- ✦Every board verified uniquely solvable before it ships
- ✦Byte-identical boards on phone and server
- ✦65 tests across engine and API
Architecture
- 01TypeScript puzzle engine
- 02Expo / React Native app
- 03Fastify level API
Services used
Tech stack
- TypeScript
- React Native
- Expo
- Reanimated
- Fastify
- Jest
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