AI-Native Engineering

Architecture & Performance

AI Vibe Coding Cleanup

Turn AI-generated code into production-grade software

AI tools are fast, but their code stops at the happy path. We review, refactor, and harden code written by Claude Code, Cursor, or any LLM, then add tests and docs. Production-grade, owned by humans, not AI-generated guesswork.

Get an AI code review

How we can help

What you get

Turn AI prototypes into owned software.

Security review

Exposed secrets, insecure deps, missing validation, and weak error handling found and fixed before they reach users.

Refactor and stabilize

Inconsistent AI-written files reorganized to one standard, with tests and CI so changes stay safe as you build.

Off the happy path

We complete the failure handling, edge cases, and backend work that prototypes skip, so real users don't break it day one.

AI-ready docs

Clear system docs and ADRs that help your engineers, and your AI tools, generate changes that match the codebase.

Observability built in

Logs and dashboards that surface what matters in production, so issues show up before customers report them.

A clean handover

You leave with code your team owns and extends, not a black box only the AI understood.

AI Vibe Coding Cleanup

Pay off your tech debt before it ships

Send us the repo. We'll review it for security, gaps, and stability, then make it something your team can ship and own.

Get an AI code review

Scope → Build → Scale

Turn technical limits into shipped fixes.

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

Case studies

What shipping at AI speed looks like

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

Self-Hosted CI/CD Infrastructure

Architecture & Performance

Building Scalable Observability for a High-Growth React Native App

3→1

analytics systems unified into a single interface

Team Training

AI-Assisted Migrations

Architecture & Performance

Training HelloFresh Engineers to Build Production Apps With React Native

2.8x

increase in knowledge over 8 weeks (25% → 71% assessment scores)

Architecture & Performance

End-to-End Product Development

Optimizing Android TV Startup for Global Streaming Platform

faster startup time on FireTV and FireHD devices

End-to-End Product Development

Self-Hosted CI/CD Infrastructure

Architecture & Performance

Launching a High-Performance React Native App on Samsung TV

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

Feature Development

Architecture & Performance

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

SEO rank, recovering from 3-9

Architecture & Performance

AI-Driven QA & Testing

Self-Hosted CI/CD Infrastructure

Enhancing Application's Performance for Expensify

faster message sending time

Architecture & Performance

End-to-End Product Development

Improving Chat Performance and Creating a Custom UI Library for Dream11

78%

bundle size reduction (from 50 MB to 11 MB)

Architecture & Performance

Feature Development

Creating React Native SDK Wrapper for Rive

100k

weekly downloads on npm

10 years of React Native → Now in your AI stack

Pay off your tech debt before it ships

Send us the repo. We'll review it for security, gaps, and stability, then make it something your team can ship and own.

Get an AI code review

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

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

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

Still have questions?

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.

Book consultation

How do you assess what needs to be fixed?

We start with a structured review covering architecture, security, test coverage, and maintainability, then prioritize based on risk and impact.

Will you rewrite everything?

No. We refactor and stabilize what’s there, rewriting only where necessary for security, performance, or maintainability.

What security issues do you typically find?

Common issues include exposed secrets, insecure dependencies, missing input validation, and improper error handling.

Can my team work alongside yours?

Yes. We often pair with your engineers to transfer knowledge and enable your team to maintain the system long-term.

What if the prototype is missing backend or API work?

We fill in the gaps. AI tools often stub or skip backends, so we complete the missing pieces to make the system functional.

Do you add tests?

Yes. We introduce tests appropriate to your stack, such as unit, integration, or end-to-end, to prevent regressions going forward.

What do we get at the end?

Production-ready code, security findings, documentation, and a handover that lets your team own and extend the system.

AI Vibe Coding Cleanup

Pay off your tech debt before it ships

Send us the repo. We'll review it for security, gaps, and stability, then make it something your team can ship and own.

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.

Check All Tools

Explore AI Infrastructure

Reassure

Performance testing companion for React and React Native

1438

stars

React Native Harness

Harness brings Jest-style tests to real native environments so you can test TurboModules like you would test your React Native app: with JavaScript.

136602

downloads / month

Rozenite

Plug-and-play panels for React Native DevTools. Install, enable, and start debugging in minutes.

665223

downloads / month

Re.Pack

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

111317

downloads / month

React Native Sandbox

Run multiple, isolated React Native instances within a single application

506

downloads / month

Insights

Worth your time, by engineers.

Explore Insights

Jul 20

Article

An AI Agent for Measured React Native Performance Fixes

React Native performance work can produce misleading results when teams rely on a single profiler run. This article introduces Metrognome, an open-source AI plugin that turns proposed fixes into repeated, gated experiments on a live app. It explains how the tool combines device control, render analysis, runtime signals, and performance guidance, shares examples from Uphold, and shows how its Performance Map and CI workflows prioritize issues and create evidence-backed PRs.

May 25

Article

Profile React Components in React Native Release Builds

@callstack/inspector brings React component profiling to React Native release builds. This article walks through the setup in an Expo app and shows how to inspect performance closer to how users experience it, without development-only debug code affecting JavaScript execution.

Jan 29

Article

Announcing AI SDK Profiler for React Native

We introduced the AI SDK Profiler plugin for Rozenite DevTools. It captures OpenTelemetry spans emitted by the Vercel AI SDK, surfaces prompts, outputs, metadata, and latency, and works with any provider, on-device or cloud.

Dec 19

Article

Visualizing the Dual-Thread Model of Lynx JS

If you’ve felt JS thread pressure in React Native, Lynx’s runtime will feel familiar and different at the same time. This article uses a simple jammer technique inspired by React Native experiments to reset expectations and provide a clear mental baseline. From there, it shows how Lynx’s dual-thread model keeps UI-critical work responsive, even when background JavaScript is completely blocked.

Dec 18

Article

Why You Don’t Have to Minify JavaScript Code in React Native Apps

JavaScript minification is standard practice on the web, but React Native follows a different optimization path. This article explains how the Hermes engine compiles JavaScript into bytecode and applies dead code elimination during that step, making traditional minification largely unnecessary. It also shows how to verify what actually ships in production by decompiling Hermes bundles.

Nov 21

Article

Memory Ownership Models: When JavaScript Meets Native Code

React Native makes it easy to pass data between JavaScript and native code, but things get complicated once you leave the synchronous path. This article explains what really happens when ArrayBuffer memory crosses the JS and native boundary, why raw pointers can become invalid during async work, how garbage collection affects native code, and what safe patterns you can use today.

Oct 14

Article

From Files to Buffers: Building Real-Time Audio Pipelines in React Native

Most audio APIs are designed around files. You generate sound, save it, then read it back for playback or processing. While simple, this workflow breaks down when you need low latency or real-time interaction. In this article, we’ll explore how to work with raw PCM data entirely in memory, construct valid WAV buffers on the fly, and transfer them efficiently to JavaScript using JSI. The result is a flexible foundation for building real-time audio features directly in React Native.

Sep 8

Article

How to Add Custom JSI Bindings in Your TurboModule (and Why You Might Need Them)

TurboModules provide a type-safe way to write native code in React Native. JSI sits underneath as a lower-level API, enabling direct interaction with the JavaScript runtime. This article explains how to safely inject custom bindings with an ArrayBuffer example.

Aug 5

Article

How Node-API Works in React Native: A Deep Dive

In this deep dive, we explain how Node-API is brought to React Native—from discovering and bundling native addons to loading them at runtime. We also walk through the design of the host system and tools that make it all work.

Jul 24

Article

Exploring Fibers: Cooperative Multitasking and Lock-Free Task Execution

This third installment in our performance series focuses on building a cooperative, fiber-based task scheduler. We explore what fibers are, how they relate to coroutines, and how to organize tasks using atomic counters instead of traditional locks. You’ll learn how to avoid blocking, manage dependencies across tasks, and profile execution with Tracy. The concepts apply across languages and runtimes, offering a foundation for designing lock-free systems that scale efficiently on modern CPUs.

Jul 17

Article

Build and Run Node-API Modules in React Native

Node-API allows you to write native modules that run not only in React Native but also in other JavaScript runtimes like Node.js. In this deep dive, we'll guide you through creating a simple Node-API module, testing it in Node.js, getting it up and running in React Native, and finally, publishing it to npm for wider use.

Jul 10

Article

Announcing Node-API Support for React Native

Node-API brings a stable, cross-platform system for building native modules in React Native, enabling faster builds, easier maintenance, and broader language support. Already widely used in Node.js, Deno, and Bun, it allows native code to interface with JavaScript in a runtime-agnostic way. This makes it possible to distribute prebuilt binaries, reuse existing native libraries, and share code across ecosystems. With support for languages like C++, Rust, and Swift, Node-API opens the door to building high-performance modules for tasks like AI, encryption, and platform API access, all without being tied to specific runtime internals.

May 21

Article

Multithreading Isn’t Free: Performance Pitfalls Visualized

This article walks through real-world examples of profiling multithreaded C++ code. It shows what happens when you throw too many threads at a problem, how to measure performance with Tracy, and why smarter scheduling beats brute force. While the code is in C++, the takeaways apply to any performance-critical system.

Apr 11

Article

Profiling React Native Internals with Tracy for Peak Performance

Profiling React Native's internals can uncover bottlenecks and provide deep insights into native behavior. This guide walks through using the Tracy profiler to instrument React Native code, collect performance metrics, and identify optimization opportunities across iOS and Android.

Mar 20

Article

Why Knowing Your App’s Bundle Contents Matters for React Native Performance

Slow app startup times can frustrate users, especially on older devices or slower networks. Expo Atlas helps you peek inside your React Native app bundle to identify large dependencies and optimize performance, even if you're not using Expo.

Mar 14

Article

Why You Should Not Re-Implement Native Features in React Native

When building React Native apps, it's tempting to re-implement native OS patterns and gestures from scratch. But this can lead to inconsistencies and performance issues, even if you use native code. A better approach is to leverage existing native components and libraries wherever possible, and only build fully custom UI when absolutely necessary.

Mar 13

Article

The Mini Guide to React Native Optimization for Web3

Building web3 apps with React Native requires careful optimization. This guide shares practical tips to manage dependencies securely, use mobile-first libraries, and connect wallets efficiently for better performance and UX.

Jun 7

Article

The Inner Workings of GPU Rendering for 2D and 3D Graphics

The GPU is the unsung hero behind the stunning visuals on our screens. This article dives into how GPUs render 2D and 3D graphics, from processing vertices and pixels to creating the final masterpiece that tricks our eyes into perceiving smooth animations.

Jun 14

Article

Technical Guide, Part 2: Integrating Hermes With React Native

React Native 0.64 adds support for the Hermes engine on iOS. This technical guide walks through the process of integrating Hermes with React Native, building on the work to compile Hermes for Apple platforms. It covers the key integration points, how to activate the engine, and what it looks like in practice.

May 26

Article

Technical Guide, Part 1: Compiling Hermes for Apple Platforms

Compiling Hermes for iOS involves configuring CMake to target Apple platforms and architectures. This guide walks through the key steps, from setting up the build pipeline to creating a universal framework that works seamlessly on both devices and simulators.

Mar 29

Article

Streamline Native Dependencies for Faster Time-to-Interactive

Unused native dependencies can slow down React Native app startup times. This guide shows how to use the depcheck tool to identify and remove unneeded dependencies, reducing app size and improving time-to-interactive by up to 17%.

Aug 8

Article

Reanimating Your React Native Experience

Gestures and animations in React Native are getting a major upgrade thanks to react-native-gesture-handler and react-native-reanimated. This guide walks through building a smooth collapsible navigation bar that runs entirely on the UI thread, even with the JS thread blocked.

Feb 17

Article

Profiling React Native Apps With iOS and Android Tools

Profiling React Native apps with native tools like Instruments, Flipper, and Hermes Debugger on iOS and Android Profiler on Android can help identify performance issues and improve user experience. This guide walks through how to use these tools to measure CPU, memory, network usage and more to optimize your app's responsiveness.

Dec 6

Article

React Native - How to Check What Passes Through Your Bridge?

Debugging the React Native bridge is crucial for optimizing performance. This guide shows how to use the MessageQueue module to spy on data passing between JavaScript and native code, so you can identify unnecessary communication that may be overloading the bridge and causing your app to freeze.

Nov 23

Article

React Developer’s Everyday Struggle - Extending Big Applications

Extending large React apps can be tricky in practice. We walk through the options we considered for adding form validation to the EEDI educational platform, and how we landed on a "function as child" pattern to meet our requirements without heavy refactoring.

Aug 29

Article

Optimizing Performance With The React Compiler

The React Compiler automatically optimizes component performance, reducing unnecessary re-renders and locking down dependencies. We walk through how it can significantly speed up apps without extra code hassle or bugs.

Dec 5

Article

Optimize Your Android Application’s Size With Gradle Settings

Optimizing your Android app's size is crucial for faster downloads, shorter startup times, and better user experience. This guide shares practical Gradle settings to reduce APK size, like enabling Proguard to remove unused code and building separate APKs per CPU architecture.

Feb 22

Article

Optimize Your React Native App’s JavaScript Bundle

Bundling your React Native app's JavaScript code with Metro can slow down build times as your codebase grows. This guide explores alternative bundlers like Re.Pack, react-native-esbuild, and rnx-kit that offer more configurability and performance optimizations to help ship less code to users faster.

Dec 21

Article

Optimize React Native Apps' Battery Drain With Mobile-Dedicated Libraries

React Native gives you freedom to build apps with JavaScript, but not all libraries are optimized for mobile. Using non-mobile libraries can drain battery and slow performance. This guide shares tips for choosing mobile-first libraries that deliver fast, efficient experiences without compromising battery life.

Jan 11

Article

Lottie vs. Rive: Optimizing Mobile App Animation

Lottie and Rive are two popular tools for creating high-quality animations in mobile apps. This article compares their performance, file sizes, and developer experience to help you choose the best option for your project.

Feb 11

Article

How to Profile Native Code in React Native Using Tracy

Profiling code is essential for uncovering performance bottlenecks. This guide walks through how to use Tracy profiler to measure execution times, identify hotspots, and optimize a React Native image processing module for faster speeds.

Feb 16

Article

How to Optimize SVG for Size and Rendering Speed

Optimizing SVGs can significantly reduce app size and improve rendering speed. This guide walks through how to use tools like SVGO to compress SVGs, measure performance impact, and automate optimization with GitHub Actions.

Dec 4

Article

How to Optimize Your Android App Startup Time With Hermes

Hermes is a JavaScript engine optimized for mobile that can significantly improve your React Native app's startup time. By generating bytecode during build time and avoiding just-in-time compilation, Hermes reduces the time needed to execute your app's logic. Enabling Hermes is a simple configuration change that can lead to a faster, more responsive user experience.

Dec 25

Article

How to Pick the Right External JavaScript Libraries for Your React Native App

Choosing the right JavaScript libraries is key to building fast, performant React Native apps. This guide shares practical tips for being selective about dependencies, analyzing bundle size impact, and using smaller specialized libraries to reduce load times.

Feb 12

Article

How to Easily Create Native Libraries With Nitro and Turbo Modules

Creating custom native libraries in React Native used to be complex, with tricky bridging between JavaScript and native code. But now, Nitro Modules make it easy to write performant native code in Swift, Kotlin, and C++ with minimal boilerplate. This article explores how Nitro Modules improve on the legacy Native Modules API and the newer Turbo Modules.

Dec 20

Article

How to Choose Tools Wisely and Build Fast-Working React Native Apps

Building fast React Native apps requires finding the right balance between native code and JavaScript. This guide shares best practices for optimizing communication over the bridge, validating arguments, and keeping abstractions on the JS side to improve performance and maintainability.

Dec 23

Article

How to Achieve 60FPS Animations in React Native

Smooth 60FPS animations are crucial for a great user experience in React Native apps. This guide shares practical techniques to achieve performant animations, including using the native driver, gesture-driven animations with React Native Gesture Handler and Reanimated, and giving JS operations lower priority.

Apr 21

Article

Hermes Performance on iOS

React Native 0.64 brings Hermes, a new JavaScript engine, to iOS. We tested it on a real-world app to see how it compares to the default JSC engine. The results? Hermes made the app start up to 40% faster, especially on older devices.

Dec 5

Article

How Can Higher-Order Components Improve Performance of React Native Apps?

Higher-order components like FlatList and FlashList can significantly boost performance in React Native apps compared to basic components like ScrollView. We explore how they optimize rendering and layout measurement for long lists, and share tips to get the smoothest 60FPS scrolling.

Jun 3

Article

Handling Multiple Native iOS Views in React Native

Handling multiple native iOS views in React Native can be tricky. This guide walks through how to use refs to control specific native view instances and communicate between the JavaScript and native layers.

Oct 28

Article

Enhance App Performance and Business Growth With Real User Monitoring

Real User Monitoring (RUM) is a powerful tool for identifying performance issues, but many companies struggle to turn the data into meaningful actions. This guide walks through how to use RUM to optimize app performance, detect problems early, and improve key business metrics like conversion rates.

Feb 4

Article

Experiment With the New Architecture of React Native

React Native's New Architecture brings major changes to how the framework works under the hood. We explore the key components like Fabric, TurboModules, and JSI, and show how migrating can help boost performance and leverage new capabilities in React 18.

Jul 1

Article

Code Splitting in React Native Applications

Code splitting is a powerful technique for optimizing React Native apps by creating multiple bundle files instead of one monolithic bundle. This article introduces the concept of code splitting and explores how it can improve performance, especially for modular apps or "super apps" built from mini apps.

Apr 14

Article

Bringing Hermes to iOS in React Native 0.64

React Native 0.64 brings Hermes, a JavaScript engine optimized for mobile apps, to iOS for the first time. We walk through the technical details of how the Callstack team worked with Facebook and Microsoft to compile Hermes for Apple platforms and integrate it with React Native.

Feb 7

Article

Bringing WebAssembly to React Native With Polygen

Polygen is a new toolkit that brings WebAssembly to React Native, compiling WASM modules to native C code for near-native performance. It enables using CPU-intensive libraries from the web in React Native apps, with some current limitations. The project is under active development to expand platform support and WASI integration.

Oct 11

Article

A Deep Dive Into React Native Reanimated v1

React Native Reanimated is a powerful but complex library for building smooth, 60fps animations in React Native apps. This deep dive explains the core concepts behind Reanimated, walking through how it allows you to declaratively define animation logic that runs on the native UI thread.

Jul 8

Podcast

React Native Ease: Platform-Native Animations Without the Extra Work

Łukasz talks with Janic from App & Flow about React Native Ease, Core Animation, Reanimated trade-offs, and performant UI animation in React Native.

Jul 3

Podcast

Why Nitro Is More Than a Faster Bridge

Marc Rousavy (Margelo) talks Nitro modules, native state, zero-copy data, Vision Camera, and why speed is only part of the story.

Jul 1

Podcast

Redraw for Effects Beyond Skia

William Candillon talks about where Redraw fits next to Skia, from physics-based rendering to camera effects, AR, and new UI patterns.

Dec 4

Podcast

From Static Hermes to Hermes V1: The Road to Default

Nicola Corti (Meta) explains the evolution of Static Hermes into Hermes V1, the performance boosts it ships, and the (experimental) path to making it the new default engine.

Nov 24

Podcast

It's Not New: How 'The Architecture' Unlocks React Native's Future

Riccardo Cipolleschi (Meta) explains why the New Architecture is now just The Architecture and how it serves as the foundation for concurrent rendering, DOM APIs, and Hermes V1.

Jul 16

Podcast

Structure Monorepo for Speed, Scale & Sanity

Discover how Nx empowers teams to build and scale monorepos without losing their sanity, from selective testing to AI-powered workflows.

Oct 15

Podcast

Superfast Nitro Modules With Marc Rousavy

Even faster React Native apps? That's possible with Nitro Modules! Tune in to the conversation with their creator, Marc Rousavy.

Nov 30

Podcast

React Native at Scale With Mike Duminy (Klarna)

Tune in to find out how the use of React Native and Re.Pack can impact organizational structure and how these tools help Klarna scale product development.

Jun 27

Podcast

React Native at Scale with Matt Hargett

Get insights from Matt Hargett on derisking large-scale projects with React Native. Learn how to maximize optimization success and future-proof your app.

Jan 16

Podcast

React Native at Scale With Rafael Mendiola

Scaling React Native across business growth stages: insights from Rafael Mendiola & Jakub Stadniczuk in a podcast episode.

Mar 28

Podcast

React Native Performance in 2024: Challenges, Solutions, Forecasts

Join us as we explore the latest developments in React Native performance optimization with experts from Expo and Callstack.

Mar 16

Podcast

Profiling in Native and React Native

Get insights into profiling your React Native app from our experts in this podcast episode.

May 11

Podcast

React Native Performance Q&A

In April 2023, we enjoyed talking about performance optimization in the US. We went to San Francisco, Los Angeles and Detroit to meet some amazing folks from the React Native community - we loved the intense thought exchange there!

Oct 28

Podcast

RNEU 2020 Conference Q&A Panel

This episode provides insights into the most intriguing aspects of React Native. Check the podcast to find out what our special guests have to say!

Oct 25

Podcast

React Native New Architecture

Join Nicola Corti and Łukasz Chludziński as they discuss all about React Native's new architecture.

Dec 18

Podcast

React Native FastIO: Nitro-Powered Performance Boost

Listen to Mike Grabowski talk about React Native FastIO, a collection of primitives for working with data in React Native and its performance benefits.

May 11

Podcast

React Native 0.64 With Hermes for iOS

Discover how Hermes boosts React Native performance on iOS and macOS, with insights into AOT, bytecode precompilation, and the future of Hermes support.

Oct 26

Podcast

Open Native and Universal Native Modules

In this episode, we dive deep into the practicalities of using native modules across different ecosystems with Open Native. Our guest, Jamie Birch (@LinguaBrowse), the creator of React NativeScript, explains the pressing problems in this area and how Open Native aims to solve them.

May 15

Podcast

Creating Performant React Native Animations

Animations and performance: friends or foes? Tune in to learn how not to break your React Native app's user experience.

Mar 14

Podcast

Building in React and React Native: 5 Years Ago & Now

In this episode, we talk the current state of React & React Native, compare it to how things were 5 years ago and give advice to newcomers in the industry.

Jan 29

Tutorial

Implementing an Android TurboModule with Kotlin

Learn how to implement a React Native TurboModule on Android, from the TypeScript spec and Codegen to the Kotlin implementation and package registration.

Jan 19

Tutorial

Working with Different Threads in Swift TurboModules

Learn how JavaScript, native module, background, and main threads interact in React Native TurboModules, and how to use GCD queues to run async work safely in Swift.

Jan 9

Tutorial

How to Add Type-Safe Constants to Swift TurboModules

Learn how to expose typed, immutable constants from a Swift TurboModule using Codegen, and get full end-to-end type safety between native and JavaScript.

Dec 30

Tutorial

Adding Event Emitters to Your TurboModule in Swift

Learn how to emit native events from a Swift TurboModule and subscribe to them in JavaScript, including proper memory management and Codegen integration.

Dec 22

Tutorial

Writing Your First TurboModule in Swift

Learn how to build a fully working TurboModule in Swift, integrate it with Codegen, and bridge it through Objective‑C inside an Expo app.

July 9, 2026

Event

From JSX to SwiftUI: How Voltra Powers iOS Live Activities

See how Voltra lets React teams build iOS Live Activities and Dynamic Island UIs without Swift by translating JSX into SwiftUI under tight native limits.

May 28, 2026

Event

Redraw and the Future of 2D Graphics on WebGPU

Join Callstack engineers Szymon Chmal and Kewin Wereszczyński on May 21 at 5 PM to explore Redraw, a new 2D graphics library for WebGPU.

April 16, 2026

Event

React Native 0.85: Animation Backend and Key Updates

A recap of React Native 0.85, covering the new animation backend, DevTools improvements, and ecosystem takeaways.

February 19, 2026

Event

React Native 0.84: Hermes v1, WebAssembly, and Ecosystem Shifts

React Native 0.84 introduces Hermes v1 by default, iOS prebuilt binaries, WebAssembly support, and improved tooling across the ecosystem.

April 23, 2026

Event

Shipping iOS Live Activities with React: The Voltra Story

How Voltra enables Live Activities and Dynamic Island views using React without writing Swift. A deep dive into iOS constraints and architecture.

January 15, 2026

Event

React and React Native in 2026: Architecture, Nitro, and What’s Next

New architecture adoption, Nitro modules, React Strict DOM, Hermes v1, and ecosystem shifts shaping React and React Native in 2026.

February 5, 2026

Event

JSX to Live Activity: The Story of Voltra

Learn how Voltra brings React to iOS Live Activities and Dynamic Island by translating JSX into SwiftUI through a custom React renderer.

January 29, 2026

Event

React Universe Meetup x Zalando, Berlin

React Universe Meetup lands in Berlin on January 29, 2026. Join Zalando and Callstack for an onsite React Native-focused evening.

December 18, 2025

Event

Building iOS Live Activities With React: Inside Voltra

Learn how to build iOS Live Activities and Dynamic Island experiences using pure JSX, no Swift or native code required.

December 2, 2025

Event

Two Threads of Lynx.js Part 2

Learn how Lynx.js uses a dual-threaded model, how its APIs work, and what it means for performance in this live session with Lukasz Chludzinski and Kewin Wereszczynski.

November 27, 2025

Event

Exploring Lynx.js and Its Two-Thread Runtime

A recap of our live session exploring how Lynx.js splits work across a main thread and a background thread.

November 13, 2025

Event

Inside Valdi: What We Learned Exploring Snapchat’s New UI Framework

A hands-on look at Valdi, Snapchat’s new UI framework: setup, architecture, rendering model, and early developer impressions.

November 6, 2025

Event

Hermes V1: What It Is, What It Isn’t, and What’s Next

Łukasz Chludziński, Szymon Chmal, and Matt Hargett unpack Hermes V1, covering what’s new, what’s changing, and what’s ahead for React Native performance.

October 30, 2025

Event

Reanimated, TanStack, Cross-Pollinating Languages & TWIR #256 Anniversary

Catch up on everything from TanStack updates and Astro insights to Reanimated deep dive and even Swift for Android. Plus, we celebrate the 256th newsletter!

October 23, 2025

Event

Building Real-Time Live Activities in Expo

Learn how to add real-time LiveActivity updates to your Expo app using Swift native modules. In this stream, we implemented Apple’s Live Activities with Evan Bacon’s library, explored ActivityKit, and discussed cross-platform development with Solito 5 and Expo UI.

September 3, 2025

Event

Ottrelite: Tracing Framework for React Native

Learn how Ottrelite brings modern, cross-platform tracing to React Native; no source build needed, with deep backend and language support.

August 7, 2025

Event

Live Dev Session: FlashList v2, Vercel AI SDK, React Compiler

This week's livestream highlighted two major releases reshaping the React and React Native landscape: FlashList v2 and Vercel AI SDK 5.

July 24, 2025

Event

Live Dev Session: Reanimated 4, Worklets, React Native Screens

This week was packed with insights on highly anticipated Reanimated 4, the power of Worklets, Screens and more.

July 15, 2025

Event

Build High-Performance Modules in React Native With Node-API

Discover how to build and share native code in React Native using Node-API: faster builds, runtime agnostic, and language flexible.

April 24, 2025

Event

Tips & Tricks From The Ultimate Guide to React Native Optimization 2025

View flattening, React 19 hooks, real DevTools tips-learn what actually helps your React Native app run faster.

April 24, 2025

Event

User-Focused Performance Tracking

Discover how Expensify defines and tracks performance metrics that actually impact user experience.

April 28, 2025

Webinar

Master JavaScript Performance in React Native (Part 2)

Learn to fix JS performance issues in React Native-from debounce bugs to Redux selectors, in this hands-on webinar with real code examples.

April 16, 2025

Event

Bring Your Favorite Language to React Native

Learn how to integrate native libraries in React Native, without TurboModules. Robert shares a practical approach using WebAssembly and introduces PolyGen.

April 24, 2025

Event

React Universe Meetup: San Francisco

Missed the React Universe Meetup SF? Watch the livestream recording soon, talks on RN performance, optimization, and build-free workflows await.

April 15, 2025

Webinar

Master JavaScript Performance in React Native (Part 1)

Watch Callstack's webinar on React Native JS performance. Learn to fix bottlenecks, leaks & FPS issues from the 2025 Ultimate Guide authors.

February 15, 2024

Webinar

Top 5 Metrics You Need to Track When Optimizing Your React Native App

Watch a webinar on optimizing React Native apps to learn the top 5 metrics every React Native team should track to improve performance, reduce load time, and boost user experience.

February 3, 2025

Event

React Native WebAssembly Release Walkthrough

Join us for a deep dive into Polygen: Callstack Incubator's breakthrough in React Native development!

March 26, 2025

Event

Running WASM in React Native Apps

Find out about executing WASM in React Native, the challenges of JIT restrictions on iOS, and how Callstack's wasm2c solution enables performant native modules.

May 16, 2023

Webinar

Practical Approach to React Native Optimization for SMEs and Enterprises

Learn how Callstack improved a React Native app’s performance and user ratings through a real-world audit. Watch the webinar to see how it was done.

July 21, 2023

Webinar

Improving React Native App Performance: Practical Tactics and Real-Life Case Studies

Learn how to improve your React Native app's performance with practical tactics, metrics, and real-life case studies from Callstack experts.

October 25, 2024

Event

Astro – Island Technology in the Name of Optimization

Next.js is the default choice, but Astro offers strong competition in some areas. Let's compare their features and differences.

Turn AI-generated code into production-grade software

Turn AI prototypes into owned software.

Security review

Refactor and stabilize

Off the happy path

AI-ready docs

Observability built in

A clean handover

Pay off your tech debt before it ships

Turn technical limits into shipped fixes.

Scope

Build

Scale

What shipping at AI speed looks like

Migrating Questrade Edge Mobile to a Faster, More Scalable Architecture

Building Scalable Observability for a High-Growth React Native App

Training HelloFresh Engineers to Build Production Apps With React Native

Optimizing Android TV Startup for Global Streaming Platform

Launching a High-Performance React Native App on Samsung TV

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

Enhancing Application's Performance for Expensify

Improving Chat Performance and Creating a Custom UI Library for Dream11

Creating React Native SDK Wrapper for Rive

Pay off your tech debt before it ships

Why teams bet on Callstack

39M+

67K+

300+

39M+

67K+

300+

Let’s find the right path for your product.

How do you assess what needs to be fixed?

Will you rewrite everything?

What security issues do you typically find?

Can my team work alongside yours?

What if the prototype is missing backend or API work?

Do you add tests?

What do we get at the end?

Pay off your tech debt before it ships

Want to build it on your own?

Reassure

React Native Harness

Rozenite

Re.Pack

React Native Sandbox

Worth your time, by engineers.

An AI Agent for Measured React Native Performance Fixes

Profile React Components in React Native Release Builds

Announcing AI SDK Profiler for React Native

Visualizing the Dual-Thread Model of Lynx JS

Why You Don’t Have to Minify JavaScript Code in React Native Apps

Memory Ownership Models: When JavaScript Meets Native Code

From Files to Buffers: Building Real-Time Audio Pipelines in React Native

How to Add Custom JSI Bindings in Your TurboModule (and Why You Might Need Them)

How Node-API Works in React Native: A Deep Dive

Exploring Fibers: Cooperative Multitasking and Lock-Free Task Execution

Build and Run Node-API Modules in React Native

Announcing Node-API Support for React Native

Multithreading Isn’t Free: Performance Pitfalls Visualized

Profiling React Native Internals with Tracy for Peak Performance

Why Knowing Your App’s Bundle Contents Matters for React Native Performance

Why You Should Not Re-Implement Native Features in React Native

The Mini Guide to React Native Optimization for Web3

The Inner Workings of GPU Rendering for 2D and 3D Graphics

Technical Guide, Part 2: Integrating Hermes With React Native

Technical Guide, Part 1: Compiling Hermes for Apple Platforms

Streamline Native Dependencies for Faster Time-to-Interactive

Reanimating Your React Native Experience

Profiling React Native Apps With iOS and Android Tools

React Native - How to Check What Passes Through Your Bridge?

React Developer’s Everyday Struggle - Extending Big Applications

Optimizing Performance With The React Compiler

Optimize Your Android Application’s Size With Gradle Settings

Optimize Your React Native App’s JavaScript Bundle

Optimize React Native Apps' Battery Drain With Mobile-Dedicated Libraries

Lottie vs. Rive: Optimizing Mobile App Animation

How to Profile Native Code in React Native Using Tracy

How to Optimize SVG for Size and Rendering Speed

How to Optimize Your Android App Startup Time With Hermes

Let’s find the right path
for your product.