The most common mistake technical founders make is spending 6 months building a perfectly architected microservices backend for an app that currently has zero users. Keep it simple, stupid.
The Frontend Decision
Option 1: React Native (Recommended for most)
If your team already knows React/TypeScript, use React Native with Expo. The ecosystem is massive, iterations are incredibly fast via OTA updates, and you can deploy to iOS and Android from one codebase.
Option 2: Native iOS (Swift/SwiftUI)
If you are building an app that relies heavily on Apple HealthKit, complex background location tracking, or intensive Apple Watch integrations, build native iOS first. Do not even think about Android until you are making $10k/month on iOS. 70%+ of fitness app subscription revenue comes from iOS anyway.
Option 3: Flutter
Great if you want custom, highly animated UIs that look identical on both platforms. However, finding good Flutter developers is slightly harder than finding React Native devs.
The Backend Decision
Use Firebase or Supabase.
Do not spin up AWS EC2 instances and write custom Node.js boilerplate unless you have a highly specific reason to do so. You need authentication, a database (Firestore/Postgres), and cloud storage for user avatars. BaaS (Backend as a Service) handles this out of the box.
The Non-Negotiables
- RevenueCat: Do not write custom in-app purchase logic. Use RevenueCat. It handles receipt validation, cross-platform syncing, and gives you out-of-the-box charts for MRR and Churn.
- PostHog or Mixpanel: Google Analytics is garbage for mobile apps. You need event-based analytics to track the funnel from Install -> Paywall View -> Trial Start.
- Sentry: You need crash reporting from day one.