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Level 4 · Production & Shipping

An app on your phone isn't a product until strangers can install it from a store, it doesn't stutter on a three-year-old Android phone, a bug fix can reach users without a week-long review, and you hear about crashes before your reviews do. Level 4 is that last mile.

You'll learn to find and fix performance problems with real profilers rather than guesses, make long lists fast, write component tests with React Native Testing Library and end-to-end tests with Maestro and Detox, avoid the security mistakes specific to mobile apps, build and sign release binaries with EAS, get through App Store and Google Play review, ship JavaScript fixes over the air safely, and wire up crash reporting and analytics. The capstone takes one app through all of it to a release candidate.

Prerequisites: Levels 1–3. Store submission needs an Apple Developer Program membership (paid, yearly) and a Google Play Console account (one-time fee), and EAS Build needs an Expo account. This course can't create those for you or run builds against them, so those lessons describe each step precisely and say where you need your own account. Everything that can run locally — profiling, tests, builds of JavaScript bundles — was run while writing.

Modules

  1. Performance: Finding & Fixing Jank — measure first: the performance monitor, React profiler, Hermes sampling profiles, and the usual culprits.
  2. Big Lists: Tuning FlatList & Using FlashList — the props that matter and when to switch to a recycling list.
  3. Unit & Component Tests with Jest and RNTL — jest-expo, testing by role and label, user events, mocking native modules.
  4. End-to-End Testing with Maestro & Detox — testing the real app on a simulator, and which tool fits which team.
  5. Mobile Security: Secrets, Storage & the Network — what an attacker can read from your binary, token storage, TLS, deep-link and WebView risks.
  6. Building with EAS & App Signing — build profiles, credentials, versioning and environment variables.
  7. Shipping to the App Store & Google Play — listings, privacy declarations, review guidelines, TestFlight and staged rollouts.
  8. Over-the-Air Updates & Release Strategy — expo-updates, runtime versions, channels and safe rollouts.
  9. Crash Reporting, Analytics & Monitoring — error boundaries, Sentry, source maps and privacy-respecting analytics.
  10. Capstone — Ship a Production-Ready App — take one app through the full release checklist.