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Technical insights from building React and React Native production-grade apps, contributing to core libraries, and solving complex cross-platform challenges.

AI
5/27/2026

Introducing Apex: A Fast, Specialized Model for React Native

Today, we are introducing Apex, our first domain-specific coding model designed for React Native. Built on Gemma 4, Apex achieves frontier-level performance at a fraction of the cost of generalized models. It is optimized for the fast, agentic workflows our teams run daily, delivering up-to-date results with fewer tool calls.

Mike Grabowski

CTO & Founder

@

Callstack

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Performance
5/25/2026

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.

Hur Ali

Software Engineer

@

Callstack

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AI
5/21/2026

Agencies or Swarms? What Small Model Cooperation Means for AI Engineering

Agentic systems may not depend only on larger models. This article examines how swarms of smaller models behave under load and what that means for distributed inference, concurrency, and infrastructure design.

Lech Kalinowski

Senior AI Systems Engineer

@

Callstack

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Super Apps
5/19/2026

Using TurboModule Substitution to Build Safer React Native Plugin Systems

Plugin systems and micro-app architectures need more than a simple allowlist for native modules. This article shows how react-native-sandbox introduces TurboModule substitution, giving hosts a practical way to expose sandbox-safe native functionality for files, storage, analytics, networking, and more.

Aliaksandr Babrykovich

Senior C++ Engineer

@

Callstack

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Brownfield
5/18/2026

Unlocking Expo Updates in an Isolated Brownfield Architecture with SDK 55

Expo Updates used to be a pain point for teams running an Isolated Brownfield architecture. This guide shows how to get it working with Expo SDK 55, including iOS packaging, the current Android workaround, and end-to-end OTA update testing. If you're shipping React Native inside an existing native app, this walkthrough helps you get setup faster without guessing through the hard parts.

Hur Ali

Software Engineer

@

Callstack

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Developer Experience
5/5/2026

Codex Ambassador: Q1 Recap Across 5 Cities

Over the past few months, we got to host Codex events across 5 cities and 2 continents. Each one had a different format and a different crowd, from big meetup energy in Berlin to one-on-one sessions in Miami. This recap covers what happened and what we want to do next.

Mike Grabowski

CTO & Founder

@

Callstack

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React Native
4/28/2026

React Native production lessons from React Universe Meetup x Zalando

React Native has already proven it can ship production apps. The harder question is how it performs in brownfield migrations, feed-heavy interfaces, native API integrations, and hardware-constrained environments. This article shares four practical lessons from React Universe Meetup x Zalando in Berlin.

Mike Grabowski

CTO & Founder

@

Callstack

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AI
4/27/2026

When to Use Apple Foundation Models on Mobile

Apple Foundation Models are most useful on mobile when the task is small, fast, local, and not worth a cloud round trip. The real value is not replacing cloud models entirely, but using on-device AI where latency, privacy, and frequency matter most.

Lech Kalinowski

Senior AI Systems Engineer

@

Callstack

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AI
4/17/2026

How Skillgym Helps You Verify Agent Skills Still Work After Every Change

Small edits to a SKILL.md can change agent behavior in ways that are hard to spot manually. This article shows how skillgym helps you test skills against real agent runners, validate the right behavior, and catch regressions before they reach production.

Szymon Chmal

Software Developer

@

Callstack

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Testing
4/14/2026

Agent React DevTools: Give AI Agents Access to React Internals

Agent React DevTools gives AI agents direct access to the React component tree, state, and performance data. Instead of relying only on UI snapshots, agents can now inspect what happens inside React and debug issues with proper context. This enables more reliable QA, better performance analysis, and deeper automation for React and React Native apps.

Mike Grabowski

CTO & Founder

@

Callstack

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AI
4/3/2026

How We Optimized Agent Device for Mobile App Automation

AI agents are powerful tools for mobile automation, but running them can get expensive and slow if they consume too many tokens. In this post, we break down how we optimized Agent Device to cut LLM token usage in half and speed up execution by 33%.

Michał Pierzchala

Principal Engineer

@

Callstack

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Stay up to date with our latest insights on React, React Native, and cross-platform development from the people who build the technology and scale with it daily.

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Article
5/27/2026

Introducing Apex: A Fast, Specialized Model for React Native

Apex is our new coding model designed for React Native. It achieves frontier coding results for mobile workflows at a fraction of the cost.
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Article
5/25/2026

Profile React Components in React Native Release Builds

Learn how to profile React components in React Native release builds with @callstack/inspector, using an Expo app setup that requires zero native code changes.
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Article
5/21/2026

Agencies or Swarms? What Small Model Cooperation Means for AI Engineering

A hands-on look at agentic swarms, distributed inference, and what small-model benchmarks suggest about future AI infrastructure.
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Article
5/19/2026

Using TurboModule Substitution to Build Safer React Native Plugin Systems

Learn how TurboModule substitution helps React Native plugin systems provide native capabilities while preserving sandbox boundaries.
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Article
5/18/2026

Unlocking Expo Updates in an Isolated Brownfield Architecture with SDK 55

Learn how to enable Expo Updates in an Isolated Brownfield setup with Expo SDK 55, including iOS packaging, Android patching, and OTA testing.
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Article
5/5/2026

Codex Ambassador: Q1 Recap Across 5 Cities

A short recap of Codex events in Berlin, Wroclaw, Warsaw, Sopot, and Miami, plus what we learned from each format and where we want to go next.
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Live Stream
Live Stream
5/14/2026

Testing AI Agent Skills Reliably With Skill Gym

Learn how Skill Gym helps test, validate, and improve AI agent skills with repeatable workflows, assertions, and model-aware feedback.
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Live Stream
Live Stream
5/7/2026

Improve Your AI Coding Workflow With Cursor Tips and Tricks

Explore practical tips for working with AI coding agents, managing context, using skills, reviewing code, and choosing the right models.
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Live Stream
Live Stream
4/30/2026

Build a React Native App With the TanStack Stack

Join Callstack’s live stream on building a React Native app from the ground up using the TanStack toolbelt.
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Podcast
5/13/2026

How AI Is Changing React Native Development and Testing

Zack Ebenfeld joins React Universe On Air to talk about how AI is changing React Native workflows, testing, QA, and day-to-day engineering work.
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Podcast
2/17/2026

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.
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Podcast
1/12/2026

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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Tutorial
March 19, 2026

The Hard Way vs. The React Native AI SDK Way: Stop Writing Custom Modules for Every Model

Learn how React Native AI uses a unified provider model to switch between cloud and on-device LLMs without rewriting application logic, enabling reliable AI experiences online and offline.
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Tutorial
March 12, 2026

Build Smarter Apps: Tool Calling & AI Orchestration Explained

Learn how on-device models in React Native can call tools, interact with external APIs, and return structured outputs you can use directly in application logic.
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Tutorial
March 5, 2026

MLC LLM + React Native: On-Device AI Without the Pain

Learn how to run third-party on-device LLMs in React Native using MLC LLM. Choose your models, run them efficiently across platforms, and keep a unified JavaScript API with React Native AI.
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Tutorial
February 24, 2026

Intelligent Fallbacks with Apple Intelligence in React Native

Learn how to use Apple’s built-in Foundation Models in React Native apps, reduce memory usage, and enable fast, fully on-device AI with React Native AI Apple.
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Tutorial
February 10, 2026

What Is the React Native AI SDK? A Complete Intro & Quickstart

Learn why on-device AI matters for React Native apps, how local LLMs behave offline, and what problems React Native AI is designed to solve from day one.
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Tutorial
January 29, 2026

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.
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Tutorial
January 19, 2026

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.
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Tutorial
January 9, 2026

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.
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Tutorial
December 30, 2025

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.
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Tutorial
December 22, 2025

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.