Migrate a complete, low-risk user journey first; preserve app identity and data compatibility before expanding the shared implementation.
Converting a native iOS or Android app to React Native is a migration project, not an automatic code translation. Existing screens usually need to be implemented again, while backend services, API contracts, design assets, and some native integrations may be reusable. The goal should be a maintainable product with less duplicated work, not a rewrite for its own sake.
Before starting, define the problem you want to solve. Perhaps two teams are repeatedly implementing the same feature, or one platform falls behind. If the real issue is an unreliable backend or unclear requirements, changing the mobile framework will not resolve it.
Audit the app beyond its visible screens
Inventory navigation, authentication, local storage, analytics, deep links, push notifications, purchases, downloads, permissions, and background behavior. Record which SDKs have maintained React Native integrations and which require custom native code. Include features that only appear during account recovery, reinstall, or network failure.
Capture a baseline from the current release: startup behavior, crash trends, important task completion rates, and support issues. Use your own measurements rather than assuming the new implementation will improve everything. Preserve a reproducible set of test accounts and scenarios.
Choose an incremental migration boundary
React Native supports integration into existing native applications. This makes it possible to migrate a bounded flow while keeping other screens native. It also introduces temporary complexity, such as navigation and state passing between the two implementations.
A settings flow or a self-contained content area can be a useful first slice, provided it exercises real data and navigation. Avoid choosing a static screen that proves little. Include loading, error, empty, and offline states so the team learns how the integration behaves under pressure.
Protect app identity and user data
Plan around the existing bundle identifier or application ID, signing setup, account system, and store listing. Users should receive a normal update where the existing distribution setup permits it. Replacing an app with a different identity can disrupt the upgrade path and should be a separate product decision.
Design local data migrations explicitly. Test an upgrade from the currently published version, not only a fresh install. Check authentication sessions, cached content, pending actions, saved preferences, notification routing, and subscription access. Keep backend changes compatible with older clients that will remain installed.
Keep native integrations behind clear interfaces
Do not rewrite a reliable native integration simply to increase the percentage of shared code. Define a small interface for the behavior the shared application needs. Document the inputs, outputs, errors, and lifecycle expectations. The underlying implementation can remain platform-specific.
This separation also helps if a third-party wrapper becomes unmaintained. The application should depend on the product capability—such as retrieving authorized data—rather than spreading package-specific calls across every screen.
Release in stages and plan recovery
Compare the migrated journey with the baseline on representative devices. Test deep links into both old and new areas, interrupted authentication, and navigation back across the boundary. Use controlled rollout options where available and watch for regressions in the actual user journey.
Recovery is not always an instant store binary rollback. Prepare server-side feature controls and a forward-fix path. Data migrations must account for users moving between supported application versions; an irreversible format change can make recovery much harder.
Decide when migration is worth it
The business case should include the cost of supporting two implementations during transition. If the current app is stable and changes rarely, a migration may not earn back that investment. If both platforms share a rapidly evolving roadmap, gradual consolidation can be more compelling.
For the opposite decision, read when to move cross-platform features to native. For a web starting point, the web-to-mobile guide explains which parts you can realistically reuse.