# One Million Checkboxes
**Stack:** React, TypeScript, Vite, Node.js, Express, Socket.IO, Redis, ioredis, @socket.io/redis-adapter, react-window, Docker, Python
**Date:** May 2026
## Overview
One Million Checkboxes is a real-time multiplayer checkbox wall designed to test scale, synchronization, and state consistency across distributed backend instances.
## Key Highlights
- Built a real-time multiplayer checkbox wall that syncs state across backend instances and stores checkbox ownership state in Redis.
- Used virtualized rendering and chunk-based loading to support a universe of 1,000,000 possible checkboxes with smooth client performance.
- Implemented atomic toggle logic with Redis Lua scripts, Redis pub/sub synchronization, and rate limiting to protect the backend.
- Added a Python load-testing bot script to simulate hundreds or thousands of concurrent users and validate system behavior.
## Features
- Support for 1,000,000 checkbox positions with chunk-based data fetching
- Virtualized rendering using react-window for efficient browser performance
- Redis bitmap storage for compact and fast checkbox state management
- Atomic ownership-aware toggle logic via Redis Lua script
- Socket.IO + Redis adapter for multi-backend real-time synchronization
- Rate limiting and chunk-room subscriptions to reduce spam and fan-out
- Active user and checked count stats streamed through Socket.IO
- Load-testing script for simulated user traffic and resilience analysis
## Tech Stack
React, TypeScript, Vite, Node.js, Express, Socket.IO, Redis, ioredis, @socket.io/redis-adapter, react-window, Docker, Python
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For more details, check out the [Projects](/projects) page or explore other [Experiences](/experience).