概要
公開日: 2026-05-14
翻訳生成に失敗したため、原文をそのまま保存しています。
原文
I am a React dev who writes Next.js, Tailwind, component libraries, and design systems every day - a world that feels completely familiar. Native does not, and for years that gap felt enormous. Every time I thought about building a mobile app, I pictured Xcode, Swift, provisioning profiles, simulator setup, App Store rules, and two weeks disappearing before I even got to "Hello World." So I did what a lot of React web developers do and stayed on the web. Until I built a real mobile app in a week. Not a tutorial app, not a counter, not another todo list. I built Sun Buddy - a native iOS app with a cute, animated sun mascot, real-time UV tracking from my location, haptic feedback, daily local notifications, persistent progress, and a sleeping nighttime state when the sun is down. Hero-image I built it with Expo, Claude Code, and Expo Skills. This is my end-to-end journey: what transferred from React, what did not, where Expo made native feel approachable, and where platform reality still showed up. The short version: I did not have to become an app developer to build this app. I had to learn the native edges around the React skills I already had. The idea: Sun Buddy The app needed to be real enough to test native development properly. I did not want to build something that could have just been a web page in disguise - I wanted to touch actual device capabilities: location, haptics, notifications, native animation, local storage, and a real build running on my iPhone. So I landed on a sunlight exposure tracker. Sun Buddy is a daily habit app that helps you hit your recommended outdoor sunlight goal - tracked by UV index from your real location. The idea was simple: you are supposed to get some outdoor sunlight every day, and most people do not. I wanted a little mascot named Sunny who reacts emotionally to your progress. Sunny has a few states: - drowsy at 0% - curious when you have started - happy when you are halfway there - absolutely radiant when you hit your goal - asleep at night when the sun is down A little weird. A little cute. The kind of app I would actually keep on my phone. mascot-stages Sun Buddy was deliberately small, which was the point. I wanted a contained app that still forced me through real native surfaces: location permissions, device APIs, haptics, local notifications, persistent state, animation, app config, and an actual device build. Those patterns are not specific to a sun mascot; they are the same patterns you hit in fitness apps, habit trackers, field tools, travel apps, internal dashboards, delivery workflows, or anything else that needs to feel at home on a phone. The setup: Expo first, Claude Code second The most important part of this experience was not that I used AI. It was that I was able to build a native app using the React mental model I already had, and that is where Expo mattered. Expo gave me the app structure, routing, device APIs, build path, and the bridge from "I know React" to "this is running on my phone." Claude Code gave me the pairing loop, and Expo Skills made that pairing loop much more useful. That distinction matters. Claude Code on its own can help you write code, but native development has a lot of details where generic advice is not enough: permissions, config plugins, EAS Build profiles, App Store constraints, native module support. These are exactly the places where stale or vague guidance wastes time. Expo Skills brought Expo-specific context into the workflow. I noticed the difference most when I asked native-specific questions. Generic AI help could tell me how to write a component, but that was not the hard part. The harder questions were things like: - Should this be a normal Expo Go flow or a dev client? - Where does this permission need to be configured? - Is this a runtime library, a config plugin, or both? - What is the right path to a real iPhone build? - What changes when I move from simulator testing to TestFlight? That is where Expo Skills mattered - they g