React Development
Hire React experts for your next project
Build new React apps, untangle old ones, and ship features fast. Design systems, rendering pipelines, state, architecture, wherever your frontend needs senior engineering support. Agents move the work forward. Experts make the calls.

Build React foundations your team can own.
Foundations that hold
We design and ship React apps like Eedi, the UK classroom platform we rebuilt from scratch with a scalable, React-first architecture.
Performance, fixed at the root
Tame state, kill unnecessary re-renders, and clean up component structure, so your UI stays fast as the app and the team grow.
Agents code, experts steer
Effective agents tuned to your codebase handle the repetitive work. Our experts review architecture, set the patterns, and own the hard calls.
Extend React to new platforms
Run your React components on mobile, desktop, and beyond with React Native, Expo Router, or Electron. One model, more surfaces.
We embed, we don't hover
We pair with your engineers, align testing layers, and set up CI that reflects how your code is actually used. Monorepos welcome.
Enterprise-grade, built in
Security, accessibility, and reliability standards proven across 100+ enterprise projects, on React apps serving billions of users.
Untangle your React frontend
Tell us your app goals and your stack. We'll map a path to better performance, DX, and maintainability, starting from your code.

Scope → Build → Scale
Turn roadmap scope into shipped features.
Scope
We map your problem, align on deliverables, and define success metrics. No surprises once work starts.
Build
Engineers ship with AI-native workflows from sprint one. Code, decisions, and ownership, not discovery decks.
Scale
Expand scope, add platforms, or hand off to your team. The stack, tooling, and raised bar stay with you.
Case studies
What shipping at AI speed looks like
10 years of React Native → Now in your AI stack
Untangle your React frontend
Tell us your app goals and your stack. We'll map a path to better performance, DX, and maintainability, starting from your code.
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.

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.
39M+
Downloads / month67K+
GitHub stars300+
React Native commits100+ 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.


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

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.
39M+
Downloads / month67K+
GitHub stars300+
React Native commits100+ 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.


We are Codex Ambassadors.
We run meetups, workshops, and hands-on sessions that help teams learn Codex and apply it in real work.
Let’s find the right path
for your product.
Whether you’re planning new work or unblocking an existing product, we’ll help you choose the right path forward.
Can you join our team mid-project?
Yes. We regularly embed with teams during critical phases, launching, scaling, or stabilizing complex apps.
How do you typically work with in-house developers?
We pair with your engineers, handle delivery together, and often support platform or architecture tracks.
Can you help us stabilize a team that’s moving too slowly?
Yes. We help uncover root causes, architecture, testing, performance, and improve delivery pace with hands-on engineering.
Can you take ownership of entire features or domains?
Absolutely. We’re often responsible for owning specific domains or refactors while collaborating closely with product and design.
Can you support CI, testing, and dev workflows too?
We do. We help teams align testing layers with architecture, and set up CI pipelines that reflect how code is actually used.
What if we use React in a monorepo or across multiple teams?
We’re comfortable designing boundaries, supporting shared packages, and working in monorepos with complex ownership and coordination needs.
How fast can you get started?
We’re built for integration. We can typically kick off within days and begin adding value immediately.
How do you use AI in our React codebase without losing control?
Agents tuned to your codebase handle the repetitive work, while our experts review architecture, set the patterns, and own the hard calls. The agents move the work forward; the engineers make the decisions.
Untangle your React frontend
Tell us your app goals and your stack. We'll map a path to better performance, DX, and maintainability, starting from your code.
We had been struggling with React Native application performance until we met Callstack.
Huỳnh Chí Hùng
Associate Director / MOMO
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.
Insights
Worth your time, by engineers.

Mobile Module Federation with Re.Pack: When Runtime Delivery Is Worth the Complexity

Less Boilerplate, More Type Safety: React Navigation 8's Typed Hooks

Keeping Screens Visible With <Activity mode="hidden">

Building Apps Where AI Generates the UI

Sparkling: The Missing App Layer for Lynx.js?

A Practical Guide to React Native Monorepo With Yarn Workspaces

Bringing CSS Clipping to React Native

How to Cleanly Swap Between React Native Storybook 10 and Your App

Integrating Swift Package Manager With React Native Libraries

Exploring Lynx JS: From Quick Start to CLI Workflows

Using Expo Libraries on Horizon OS: A Guide to Compatibility

Getting Started With Expo on Meta Quest

Bridging Animated.Value and SharedValue in React Native

Debugging Android Connectivity Issues with Metro Bundler

How to Use Liquid Glass in React Native

React Native Enterprise Framework is now Rock

Introducing Rozenite: A Plugin Framework for React Native DevTools

Performant and Cross-Platform Shimmers in React Native Apps

New in Re.Pack 5.1: Preloading Remotes, Runtime Hooks, and Faster Startups

Re.Pack 5: Mobile Microfrontends, 5x Faster, Less Configuration

Your Next React Native App Will Still Be Done With Paper (2.0)

Your React Native Offline Tool Belt

Why Is It Worth to Automate Your Dependency Management with `Autolinking`?

Typed Redux

Type-Checking React and Redux (+Thunk) With Flow - Part 2

The Complete Developer Guide to React 19, Part 3: Upgraded Support

The Story of Rewriting React-Native-Opentok and the Challenges Encountered

The React Native CLI Has a New Home

The Power of GraphQL Directives

The Complete Developer Guide to React 19, Part 1: Async Handling

Sweet Render Hijacking With React

Setting Up Notifications With AWS Amplify Gen 1

Solving Swift Modular Header Issues in React Native for Good

Shaping the Future of Super Apps in React Native

Setting up React Native Monorepo With Yarn Workspaces

Sending Events to JavaScript From Your Native Module in React Native

Receiving a Live Stream With Amazon IVS in React Native

ReanimatedArc - Build Circular Animated UI Elements in React Native

Releasing React Native 0.63.1

React Native: Handling Language Changes on Android the Right Way

React Native and Native Modules: The Android SyncAdapter

React Native Paper 5.0 - What’s New?

React Native Paper 4.0 - What’s New?

React Native CLI 3.1.0 and 4.0.0 - What's New?

React Native Animations Revisited - Part III

React Native Animations Revisited - Part II

Make a React Hook out of Your Native Module

Manage Async Code Like a PRO With RxJS

Introducing the OMH Cloud Storage Module

Introducing React-Native-iOS-Kit

Introduction to the React Native OMH Maps Library

Implementing Code Splitting in React Native with Re.Pack

How to Use Module Federation With Re.Pack 3

How to Build a Chrome Extension: A Step-by-Step Guide

How to Make Mobile Payment in a React Native App With Stripe and Expo in 15 Minutes

How to Debug Faster and Better with Flipper

How to Create a Universe in React VR

How Can React Native Paper Help Startups and Enterprises?

How Did Gutenberg Change Content Creation With React Native?

How Is Linaria Different From Emotion and Styled Components?

Exposing SwiftUI Views to React Native: An Integration Guide

Grow Your Business With React Native SDK Wrapper

Getting Started With ReasonML and React Native

From Native to Multiplatform Development: Unpacking Kotlin and Compose

ECMAScript ES8 and Beyond

Develop React (Native) Apps Like a PRO

Custom Screen Transitions in React Navigation

Color Your Apps in React Native Using Material Palette

Building Component Libraries for React Native Apps

Challenges and Opportunities of Building React and React Native Apps - Discussion With Wix.com

Android Drawer and StatusBar Done Right for React Native

Announcing React Native for Apple Vision Pro

Announcing React Native Tab View 2.0

Announcing Rebolt

Amazing React Native Apps with Apollo React

Adding an Example App to Your React Native Library

A Successful Cooperation With a Client Doesn't End at Software Development

Open Mobile Hub: Non-GMS and Cross-Platform Possibilities

Module Federation






















































































