PoseCompose is a production-ready Vite + React + Tailwind SPA that lets you upload a background, add multiple individual portraits, and—via a hardened Express proxy to Google’s Gemini 2.5 Flash “Nano Banana” model—cleanly remove backgrounds, stitch subjects in order, and generate a realistic group photo with consistent lighting, scale, and pose. It caches nothing sensitive client-side, tracks usage with GA4, deploys to /var/www/apps/posecompose behind an nginx HTTPS vhost, and keeps the Gemini API key secured in /etc/posecompose-api.env, making it both a polished user experience and an operationally robust showcase. The project won Google DeepMind’s Nano Banana Hackathon on Kaggle, chosen from 832 submissions worldwide.