React Native Brownfield
Incrementally move your iOS and Android apps to React Native without breaking
Tooling for introducing React Native into existing native apps incrementally.
What you get
Bridgeless config, Fabric, TurboModules, library updates, and regression fixes across iOS, Android, tvOS.
We map required changes and risk areas, then structure the upgrade into manageable phases, not a big bang.
Concurrent React features like transitions and Suspense for data fetching that improve perceived speed.
Interop limits, unsupported components, native module deadlocks, view flattening, caught before production.
How we work together
Our senior engineers join your team to ship features, guide technical decisions, and strengthen delivery.
We take agreed work from technical planning to release, with clear responsibilities and progress you can see.
We address a performance, migration, or infrastructure challenge, or run training around your team’s needs.
Case studies




Migration to New Architecture
We migrated a global OTT app to the New Architecture: 6 RN versions upgraded, 450+ legacy tests rewritten, 10+ platforms covered.
We had been struggling with React Native application performance until we met Callstack.

We’ll connect you with the right expert within 24 hours.
Still have questions?
Often, yes. We handle the upgrade as part of the migration, since the New Architecture depends on recent React Native versions, and we plan both as one coordinated effort.
Not automatically. The main reasons to move are future compatibility and new capabilities like concurrent React features such as transitions and Suspense, which can improve perceived speed.
We structure the upgrade into manageable phases around your roadmap, not a big bang. Some work can be prepared early, with a controlled cutover and focused stabilization to finish.
We handle library updates as part of the migration and catch interop limits and unsupported components before production. Where needed, we apply replacements or interop solutions.
Legacy native modules that rely on old bridge behavior or heavy main-thread work can deadlock once you switch. We move them to TurboModules and Fabric and fix regressions across iOS, Android, and tvOS.
Yes. We map the required changes and risk areas, then phase the work around your roadmap so your team keeps delivering while we move you off the legacy stack.
The migration is agent-accelerated but led by Core Contributors, so expert engineers direct the work and review what lands. AI speeds up the repetitive changes; our engineers stay accountable for the result.