React Native Brownfield
Incrementally move your iOS and Android apps to React Native without breaking
Migration to React Native
Tooling for introducing React Native into existing native apps incrementally.
What you get
Custom AI agents do ~70% of the work: screen inventory, UI migration, business logic, baseline tests. What used to be a 12-month rewrite lands in 3–4 months.
A managed engagement from the team that builds React Native. Engineers own architecture, review, and hardening on every screen we deliver.
Matched to your platform's look, feel, and responsiveness, with every screen benchmarked with Reassure. No visible difference during the transition.
Experts set the foundation before any agent writes a line: lean, best-practice React Native, not generated debt.
Discovery ends with a data-backed recommendation, not a default. Brownfield keeps your app live, screen by screen on Rock; greenfield gives a clean architectural reset.
Pricing tracks screens and complexity; per-line pricing rewards bloat. You know each phase's cost upfront and can stage the investment.
Each migrated screen targets iOS, Android, and Web from a single codebase (~90% code sharing), extendable to TV and desktop.
Onboarding guides, workflows, and the migration skills we configure for your codebase. You own everything we build and run it without us.
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 React Native
Custom AI agents set the pace; the team that builds React Native owns the quality. Get a plan for adopting React Native quickly.
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?
When continuity matters most, we migrate brownfield: screen by screen while your app stays live, each screen validated in production and independently rollback-able - no big-bang risk. When a clean reset is the better call, we run greenfield in parallel with a planned cutover.
We match each screen to your platform's look, feel, and responsiveness, and benchmark every migrated screen with Reassure. Performance is validated continuously, not as a post-migration afterthought.
We provide onboarding guides, workflows, training, and handover so your team can maintain the shared codebase without us. You own everything we build.
Yes. Brownfield migration lands screen by screen, so you can plan the rollout and see progress as it lands. Whether that or a greenfield rebuild fits better is exactly what Discovery answers - we recommend, you decide.
This is a managed engagement, not a script you run: roughly 70% custom AI agents, 30% expert engineering - and 100% of the quality on us. Agents handle screen inventory, UI migration, business-logic translation, and baseline tests; engineers own architecture, state, and performance, and review every screen before delivery.
Our agents run under expert engineering oversight with full quality ownership, so every change is reviewed before it lands. The AI accelerates delivery; our engineers stay accountable for what ships.
Pure AI migration produces code bloat, web-style technology choices, and broken architecture - we've seen ~5% of an app's functionality generate hundreds of thousdands lines of code. Our agents are configured for your codebase, every output is reviewed by React Native experts, and we own the delivery outcome.
Yes - speed and quality come from different places. Agents supply the pace; the people who build React Native supply the quality. Architecture is set before agents write code, every screen is expert-reviewed and benchmarked with Reassure, and each lands in production independently rollback-able.
It depends on your app, and that's the point - we recommend, not push. Brownfield suits apps that must keep shipping: screens land incrementally, validated in production. Greenfield is often faster for smaller apps or codebases with unrecoverable technical debt. Discovery ends with a recommendation grounded in your codebase, not a default.