Build a Mobile App With AI (The Honest Guide: PWA First, Native When It Earns It)
'I want it on my phone' has three answers at three price points — and most people are sold the expensive one first. The decision framework, then both builds.
Here's the secret the app-builder ads skip: most 'I need a mobile app' wishes are actually 'I want my thing on the home screen, full-screen, working offline' — and the web can do ALL of that, today, free, with the app you already built. That's a PWA (progressive web app). True native apps earn their (much higher) cost in specific situations. This guide is the decision first, because the decision is where the money is lost.
The decision in one test
Go native when you need: push notifications on iPhone that genuinely matter (the web's iOS notification story remains the weak spot), deep hardware (background GPS, Bluetooth devices, health sensors), store discoverability as a strategy, or in-app-purchase economics. Everything else — your trackers, dashboards, booking pages, portals, games from this site — ships as a PWA. Rule of thumb: build the PWA in an hour today; let real users demanding a store listing be the evidence that triggers the native project.
Path A — The PWA hour
Convert my web app (file below) into an installable PWA: a manifest (name, short_name, theme/background colors matching my design, icons — generate SVG icon code I can export at the required sizes); a service worker that precaches the app shell so it OPENS offline, with a sensible strategy for my API calls (cache-then-network for [the weather data], queue-and-retry for [writes] if feasible — explain what you chose); an unobtrusive install prompt; an offline indicator in the UI instead of silent failure. List exactly how I test installation on iPhone (Share → Add to Home Screen) and Android, and what offline behavior I should verify. Complete files. [paste]
Test on your actual phone, add to home screen, toggle airplane mode. For 80% of readers, the tutorial happily ends here — icon, splash, full-screen, offline shell, zero gatekeepers, updates by uploading files.
Path B — Native via Expo, eyes open
When the test above says native: React Native + Expo is the sane route — JavaScript (your AI writes it fluently), one codebase for both platforms, and Expo handles the build machinery. The honest differences from everything you've built: there's a real toolchain (Node, the Expo Go testing app on your phone), components instead of HTML (View/Text/Pressable — Claude translates, but you're in a new land), and an edit-save-reload loop on your actual device. Start by PORTING something small you already have — the habit tracker is ideal — because known logic isolates the new-platform learning:
Port my habit tracker (web version below) to React Native with Expo. Walk me through setup from zero on a Mac/Windows: installing Node, creating the Expo project, running it on my phone with Expo Go. Then the app: same features, native look per platform, AsyncStorage replacing localStorage, and my Supabase wiring carried over (supabase-js works in React Native — confirm the config differences). Generous comments; flag every place mobile conventions should differ from my web version. [paste]
The store-publishing reality map
Budget the truth: Google Play is $25 once and days of review; Apple is $99/year, stricter review (finicky about web-wrapper-feeling apps, demands sign-in-with-Apple if you offer social login, takes its cut on digital purchases), and rejection rounds are normal, not personal — read the rejection, fix, resubmit. Both want privacy policies, screenshots, and data-usage declarations (AI drafts all of it; you verify honesty). Expo's EAS service builds the binaries so you never touch Xcode/Gradle directly — accept that gift. First submission to approval: think weeks, not days.
The hybrid most indie apps actually choose
Quietly common endgame: PWA for everyone, native only where it pays — or web app + the Telegram-bot pattern for notifications, skipping stores entirely. Stores are a channel, not a graduation ceremony. The product is the thing people use; you've been building those all along — this chapter was just about which doorway they walk through.
Keep going
Need somewhere to put it live? See where to host AI-built sites. Compare tool costs on the pricing tracker (or stick to the free options), then pick your next build.