AI-Native Engineering

The fastest way to ship React Native products

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.

Book a call
Explore services

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
End-to-End Product Development
AI-Assisted Migrations
Architecture & Performance

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
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React Development
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Next.js Development
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Expo Development
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Node.js Development
C++ Development

Capabilities

Module Federation Development
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Generative UI Development
MCP Server Development

Design

Feature UX/UI Design
Cross-Platform Design Systems
Feature Development

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
Feature Development

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.

App Development

Super App Development
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Mobile App Development
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Web App Development
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Streaming App Development
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VR App Development
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Desktop App Development
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AI-Native Development

Generative AI Development
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Voice Agent Development

Product Design

Cross-Platform Product Design
TV Product Design and 10-Foot UX
Rapid Prototyping for Real Devices
AI Product UX
End-to-End Product Development

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
End-to-End Product Development

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
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Migration to Self-Hosted Infrastructure
Migration to Modular Architecture
Migration to Expo
Migration to Next.js

React Native Modernization

Migration to New Architecture
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React Native Upgrades
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UX Modernization
AI-Assisted Migrations

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
AI-Assisted Migrations

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
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AI Vibe Coding Cleanup
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Tech Debt Reduction
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Native & Low-Level

React Native Modules Development
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React Native Brownfield Integration
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C++ Library Integration for React Native
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Shared Native Core for Cross-Platform Apps
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Custom High-Performance Renderers
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Architecture & Performance

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
Architecture & Performance
AI-Native Engineering

The fastest way to ship React Native products

For over a decade, we've delivered React Native for teams with demanding production requirements. Today, we pair that expertise with custom AI Agents, so you ship more.

Book consultation

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

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AI-Assisted Migrations
End-to-End Product Development
Self-Hosted CI/CD Infrastructure

Migrating iOS and Android Apps to React Native for AutoZone

2x

growth in mobile user base during the migration period

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Architecture & Performance
AI-Assisted Migrations
AI-Driven QA & Testing

Migrating Questrade Edge Mobile to a Faster, More Scalable Architecture

33%

fewer re-renders across most features

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Feature Development
Architecture & Performance

Migrating AutoZone’s Storefront to Next.js for Better Performance and SEO

#1

SEO rank, recovering from 3-9

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End-to-End Product Development
Self-Hosted CI/CD Infrastructure
Architecture & Performance

Launching a High-Performance React Native App on Samsung TV

5

platforms under one RN codebase: tvOS, FireTV, Tizen, LG, Vizio

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AI-Assisted Migrations
Self-Hosted CI/CD Infrastructure

Migrating a Legacy React Native App to Expo for Faster Builds and Simplified Releases

6x

faster builds after replacing Jenkins with EAS

Case Study Cover
AI-Assisted Migrations
Feature Development
End-to-End Product Development

Modernizing 7Cup's React Native Codebase and Adding Platform Features

130%

increase in users post-upgrade

Case Study Cover
Architecture & Performance
AI-Driven QA & Testing
Self-Hosted CI/CD Infrastructure

Enhancing Application's Performance for Expensify

5x

faster message sending time

10 years of React Native → Now in your AI stack

Ship your product at AI speed.

Senior engineers and agents, building cross-platform products faster without lowering the bar. Let's scope what that looks like for your team.

Book consultation

Why teams bet on Callstack

From billion-user apps to React Native core, this is why teams choose Callstack when they need to move fast and get it right.

Rocket ascending into a blue night sky with digital binary code forming its smoke trail.

10 years in React Native. Now shaping agentic engineering.

For a decade, we have helped define how teams ship with React Native. Now we are helping shape how they work with agents.

Founded in 2016 ·Backed by Viking Global Investors

React Foundation members. Core Contributors.

We are founding members of React Foundation and Core Contributors to React Native. You get direct access to people close to the decisions shaping the frameworks you use.

Open source since 2016. Our code runs in your app.

We contribute to React Native and maintain libraries across its ecosystem. Our code runs in apps used by millions of people every day.

Open Source Projects

39M+

Downloads / month

67K+

GitHub stars

300+

React Native commits

100+ Enterprise clients with 7B+ users.

We work with teams shipping at real scale. You get a partner used to high-stakes products, not learning on your roadmap.

Agent Conf. The conference for the Agentic era.

The conference we built for the shift from writing code to orchestrating agents.

Agent Conf
Gradient background blending white, light blue, and purple shades with smooth transitions.Man wearing glasses and a Stanford sweatshirt speaking into a microphone during a presentation.

We are Codex Ambassadors.

We run meetups, workshops, and hands-on 
sessions that help teams learn Codex 
and apply it in real work.

Check Events
Rocket ascending into a blue night sky with digital binary code forming its smoke trail.

10 years in React Native. Now shaping agentic engineering.

For a decade, we have helped define how teams ship with React Native. Now we are helping shape how they work with agents.

Founded in 2016 ·Backed by Viking Global Investors

React Foundation members. Core Contributors.

We are founding members of React Foundation and Core Contributors to React Native. You get direct access to people close to the decisions shaping the frameworks you use.

Open source since 2016. Our code runs in your app.

We contribute to React Native and maintain libraries across its ecosystem. Our code runs in apps used by millions of people every day.

Open Source Projects

39M+

Downloads / month

67K+

GitHub stars

300+

React Native commits

100+ Enterprise clients with 7B+ users.

We work with teams shipping at real scale. You get a partner used to high-stakes products, not learning on your roadmap.

Agent Conf. The conference for the Agentic era.

The conference we built for the shift from writing code to orchestrating agents.

Agent Conf
Gradient background blending white, light blue, and purple shades with smooth transitions.Man wearing glasses and a Stanford sweatshirt speaking into a microphone during a presentation.

We are Codex Ambassadors.

We run meetups, workshops, and hands-on 
sessions that help teams learn Codex 
and apply it in real work.

Check Events

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.

Check All Tools
Explore AI Infrastructure
Agent Skills

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

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
React Native Bottom Tabs

Native Bottom Tabs for React Native

324677
downloads / month
Re.Pack

A webpack-based toolkit to build your React Native application with full support of webpack ecosystem

111317
downloads / month
Liquid Glass

iOS Liquid Glass in React Native

157692
downloads / month

Insights

Worth your time, by engineers.

Explore Insights
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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.
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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.
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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.
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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.
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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.