I Turned My Web App Into a Mobile App in One Day With Expo

Omar took coloring.page, a working web app for turning photos into printable coloring pages, and converted it into a native iOS app in about a day using Expo. The app shares the same Supabase database and API infrastructure as the web version, so nothing had to be rebuilt from scratch. The Cala AI story kicked things off. A 19-year-old built a calorie-tracking app that wraps a vision model, took it to $50M in revenue, and sold it to MyFitnessPal. The point: a couple of API calls and a clean interface is enough to build a real business. Expo is a framework that lets you take an existing React web project and ship it as a native iOS and Android app. Omar installed it, told Claude Code to set things up, and had a working app connected to his database within 10 minutes. The demo ran live. Title colour changed in real time on a physical device. Animated particles pulled from a CodePen snippet were dropped into the upgrade modal. A settings screen was rebuilt by pasting a Mobbin screenshot directly into Claude Code as a UI reference, and it came back looking clean in seconds. Design resources used throughout: Mobbin for UI inspiration across real apps, CodePen for animation snippets, IconScout for Lottie animations, remove.bg and Claude Code itself for stripping backgrounds off generated assets. Splash screen elements were also started live. Prompts were written for individual coloring-related objects (chunky crayons, a paintbrush, an eraser), generated one at a time in Flux, then handed to Claude Code to remove backgrounds and animate them flying onto the screen. The next step is paid ads and influencer marketing, targeting parent and family accounts on TikTok where the coloring pages audience already lives.