AI-Native Engineering

The fastest way to ship React and React Native

For over a decade, we've delivered React and React Native for teams with demanding production requirements. Today, we pair that deep expertise with custom AI agents, so you can deliver scopes that would normally require twice the headcount or twice the time.

Why teams pick callstack

Agentic delivery,
led by Core Contributors

AI accelerates the output, but our senior engineers ensure your architecture scales, performs, and works flawlessly in the real world.

One partner across mobile, web, desktop, and TV.

One React codebase covers every platform. Add them now, or bring in later as the product grows.

Complex migrations in quarters, not years.

AI agents handle the repetitive heavy lifting. Our engineers own the core architectural decisions.

Deep engineering for complex native work.

We solve the hardest performance bottlenecks. 
Your product stays fast and stable as it scales.

Expert execution. Agentic speed.

Feature Development

Scale delivery with
AI-native engineering

Senior product engineers join your team to clear backlog, ship roadmap work, and take high-impact implementation off your internal leads. AI-native delivery lets a small expert team cover more ground without lowering your bar for review, testing, or architecture.

Stacks

React Native Development

Work with Core Contributors and engineers experienced in high-scale React Native apps. Move faster, avoid pitfalls, build with confidence.

React Development

Senior React engineers for complex web products. Architecture, design systems, rendering pipelines. Take ownership where it's needed.

Next.js Development

Scale and maintain complex web apps with engineers who know Next.js past the happy path. Migrations, App Router, self-hosted infrastructure.                        

Expo Development

Build performant, native-quality apps faster. We help teams design, develop, and ship reliable Expo apps from MVPs to production-scale platforms.

Node.js Development

Backend engineering that keeps pace with your React Native product. APIs, services, and integrations built to handle real production load without slowing the team down.

C++ Development

High-performance native modules and cross-platform core logic for products that push hardware limits. JSI and TurboModule expertise included.

Capabilities

Module Federation Development

Architect micro-frontend systems that let multiple teams ship independently. Shared infrastructure that scales without breaking delivery across codebases.

Generative UI Development

Build interfaces that adapt dynamically to AI output. Components that handle variable structure, streaming responses, and real production conditions reliably.

MCP Server Development

Connect your product to AI agents with custom MCP servers built to your stack and security requirements. Safe integrations with internal tools, data sources, and APIs.

Start with a codebase review

Give us 60 minutes in your repo. We'll come back with what a senior AI-native team would prioritize and how we'd staff it.

Move roadmap work faster
Get more done with a smaller team
Raise the team's bar while we work

End-to-End Product Development

Ship every platform from one codebase

We take full ownership of your product, from architecture to release. One senior AI-native team builds and ships it end to end, so you get to market faster with less delivery complexity.

Apps

Super App Development

Build modular mobile platforms where teams ship updates independently and plug in new services without breaking what already runs.

Mobile App Development

One codebase, every platform. Ship native iOS and Android faster without the cost of maintaining two separate teams and two separate builds.

Web App Development

Build reliable, scalable web applications with React. From SPA and SSR to micro frontends and design systems, architecture that grows with the product.

Streaming App Development

Deliver consistent video experiences across mobile, web, smart TVs, and set-top boxes from one shared codebase. Proven at scale.

VR App Development

Build immersive VR experiences using React Native and the same patterns your team already knows. Cross-platform potential from day one.

Desktop App Development

Extend your mobile or web product to macOS and Windows with React Native. Native desktop feel without a separate codebase or team.

AI-Native

Generative AI Development

End-to-end generative AI features across iOS, Android, and web. One team covers UX, model integration, observability, and release.

Voice Agent Development

Build voice-driven AI experiences that work reliably in production. Streaming responses, session management, and cross-platform delivery handled end to end.

Start with a product scoping call

Tell us what you're building and who it's for, and we'll come back with a platform plan, team shape, and a realistic timeline to first release.

Launch on more platforms
Work with one senior team
Reach market faster
Extend the product later

AI-Assisted Migrations

Execute complex migrations at agent speed

We move teams off legacy systems without the cost and drag this work used to carry. AI-native workflows make complex migrations easier to plan, execute, and justify.

Technology Migrations

Migration to React Native

Move from native iOS/Android, Xamarin, Flutter, or Ionic to React Native with a clear migration path, managed risk, and a production-ready result.

Migration to Self-Hosted Infrastructure

Cut platform dependency and take full control of your delivery stack. We migrate teams off hosted services to self-hosted, secure infrastructure.

Migration to Modular Architecture

Break a monolithic codebase into independently deployable modules. Teams ship faster without coordination overhead slowing every release down.

Migration to Expo

Move to Expo's managed workflow and EAS infrastructure. Faster builds, simpler releases, and full access to the modern React Native ecosystem.

Migration to Next.js

Migrate to Next.js and unlock App Router, Server Components, and flexible rendering. Faster loads, leaner bundles, and a modern full-stack architecture.

React Native Modernization

Migration to New Architecture

Adopt Fabric, TurboModules, and JSI for better performance and native interop. We handle compatibility, custom modules, and validation end to end.

React Native Upgrades

Upgrade to the latest React Native without the risk. Breaking changes, native dependency conflicts, and library issues resolved before they block release.

Migrate to a new stack with agents

Send us the current stack and where you want to land.
We'll come back with the migration path and the timeline.

Move off legacy faster
Choose the right migration path
Reduce migration risk
Build faster after migration

Architecture + Performance

Solve your hardest engineering challenges

We help products get past technical limits that slow delivery and hurt quality. Senior engineers solve the underlying issues so teams can ship faster with more confidence.

Performance

React Native Performance Optimization

Diagnose and fix what makes your app slow. Re-renders, animation jank, slow startup, memory leaks — root causes fixed, not patched over.

AI Vibe Coding Cleanup

AI-generated code moves fast and accumulates risk. We review, refactor, and stabilize it to meet production standards before it becomes a blocker.

Tech Debt Reduction

Pay down the debt that slows every sprint. We audit, prioritize, and refactor the parts of the codebase that hurt delivery and team confidence most.

Native & Low-Level

React Native Modules Development

Custom TurboModules for platform APIs, hardware integrations, and performance-critical paths that off-the-shelf libraries can't reach.

React Native Brownfield Integration

Add React Native to an existing iOS or Android app without a full rewrite. Migrate screen by screen, at whatever pace makes sense for the team.

C++ Library Integration for React Native

Bring C++ libraries into React Native via JSI and TurboModules. Maximum performance for computation-heavy features, with full cross-platform reach.

Shared Native Core for Cross-Platform Apps

Write critical business logic once in C++ or Rust and run it across iOS, Android, web, and desktop. No drift, no duplication, no platform-specific bugs.

Custom High-Performance Renderers

Build custom rendering pipelines for UIs that standard React Native components can't deliver. GPU-accelerated graphics, custom layout engines, specialized drawing.

Get an architecture review

Point us at the code that's slow, flaky, or hard to ship. Our senior engineers come back with root causes and a prioritized fix plan.

Improve speed and stability
Remove engineering bottlenecks
Get the hard work done
Strengthen the foundation

Scope → Build → Scale

The fastest way to ship React Native products.

Scope

We map your problem, align on deliverables, and define success metrics. No surprises once work starts.

Start in weeks, not months
Fixed scope before work starts
1 week

Build

Engineers ship with AI-native workflows from sprint one. Code, decisions, and ownership, not discovery decks.

3 Callstack engineers ship like 6
Impact visible before sprint two
1-12 months

Scale

Expand scope, add platforms, or hand off to your team. The stack, tooling, and raised bar stay with you.

You own everything we build
Move faster on the next launch
AS NEEDED
Test
Code
engineer
Review
Deploy

One engineer, multiple agents.
Shipping in parallel.

Our engineers orchestrate. Code generation, testing, migrations,
and reviews run simultaneously across multiple agents.

Callstack Delivery Model

Case studies

What shipping at AI speed looks like

10 years of React Native → Now in your AI stack

Choose the AI-Native team with the right foundation.

Bring us the product, workflow, or rollout under pressure.
We’ll show the fastest safe path forward.

Book consultation

Open Source

Want to build it on your own?

We open-source the tools behind our delivery model.
Use them, fork them, or let us run them for you.

Agent Skills

Callstack’s best practices on React Native performance optimization, upgrading, and CI workflows.

1374
stars
React Native Brownfield

Incrementally move your iOS and Android apps to React Native without breaking.

516
stars
React Native Testing Library

Simple and complete React Native testing utilities that encourage good testing practices.

9460312
downloads / month
React Native Builder Bob

Simple set of CLIs to scaffold and build React Native libraries for different targets.

1525894
downloads / month
React Native Pager View

React Native wrapper for the Android ViewPager and iOS UIPageViewController

4723460
downloads / month
React Native AI

On-device LLM execution in React Native with Vercel AI SDK compatibility

22123
downloads / month
Re.Pack

Webpack-based toolkit to build your React Native application with full support of webpack.

111317
downloads / month
React Native Bottom Tabs

Native bottom tab bar components for React Native, built on top of native APIs for iOS and Android.

324677
downloads / month
Liquid Glass

Native iOS 26 liquid glass visual effect for React Native apps, with fallback on unsupported platforms.

157692
downloads / month

Insights

Worth your time, by engineers.

cover
Jan 12
·
Podcast

Building v0 iOS and Fixing React Native Along the Way

A technical look at building v0 mobile with React Native and Expo, covering iOS-first decisions, native modules, and fixes pushed to React Native core. Featuring Fernando Rojo, Szymon Rybczak, and Oskar Kwaśniewski.
cover
Feb 17
·
Podcast

From Teddy Bears to Voice Agents: Kraen Hansen on Voice AI, Local-First & App Security

What happens when you combine voice agents and teddy bears? A hands-on look at local-first systems, voice AI, and security lessons from poking real apps.
No items found.
cover
Mar 3
·
Article

Building Apps Where AI Generates the UI

Most AI apps wrap powerful models in a simple chat interface. This piece explores a different direction: letting the model generate the interface itself. Instead of returning text, it describes what the user should see next. The UI is decided at runtime, adapting to each user and context rather than being hardcoded in advance. The article walks through the architecture behind this pattern and shows it in practice with a project that turns static PDF forms into adaptive, AI-driven interviews.
cover
Mar 24
·
Article

From Brownfield Complexity to AI-Supported React Native Migration

Brownfield migrations often fail due to ordering and integration gaps, not framework limits. This article explains how an AI-supported workflow helps enforce correct sequencing across packaging, startup, and runtime validation.
cover
April 2, 2026
·
Webinar

AI-Assisted Migrations to React Native: From Months to Days

Reduce migration time from months to days by using AI in real React Native workflows. Learn when to migrate incrementally and when starting fresh is the better option.