Callstack + Open Source = 💙

“To support and inspire other developers and companies to launch their products for everyone, at the same time, on every platform” - these words greet guests visiting Callstack office. It’s easy to write such a sentence on the wall, but it means nothing without people that truly believe it. It is something that we appreciate the most, people that are supportive and ready to share their knowledge. People that always seek new knowledge and want to constantly develop their skills. People that are specialists in their domain and inspire others to explore different areas of expertise. That’s what Callstack is about. People.

If you are that kind of person it’s natural for you to help your colleagues with their daily issues. Every day you have the opportunity to discuss the ideas while having dinner or drinking a coffee in the morning. This is how our greatest Open Source libraries have come to life. You could’ve heard of Linaria, Paper or Haul. All of these are ideas that began somewhere in our office…

Community we create

We understand that not everyone has an opportunity to work in the same place as we do, and we know that there are much more supportive and inspiring people around. That’s why we are investing a lot into the community. We are a part of something bigger, something that goes far beyond the bounds of our office, country or continent. We know how much we owe the community and we want to give back even more, as much as we can.

We are really passionate about React Native. We use it on a daily basis. That’s why except working on our own libraries, our developers are constantly contributing to the React Native repository and helping to maintain several community repositories, such as:

But we won’t stop here. We understand the importance of keeping the main repository of React Native clean and we know how much time it takes to keep it healthy and organized. That’s why we’d like to help Facebook and the rest of the community with cleaning up the issues section of the GitHub repository.

We’ve started from organizing a hackathon with an issue triage session last month. Our group managed to close almost two dozens of issues as well as send a few PRs to the community repositories, closing some crucial issues. It was really intense afternoon.

Community is continuously working on such things and we want to be no different. We understand that this one time is not enough and we want more! We’d like to repeat such an event, not only once, but rather keep repeating it every month. The next one is going to happen on May 30th.

Open Source contributors

We want to make all of our Open Source actions inclusive. Recently we’ve released react-native-open-source-board, allowing more developers to quickly get up and running with their contributions. Naturally, in the future are planning to open our hackathons to the larger audience, but we still need some time to sort the things out. Stay tuned.

Ultimately, we’d like to thank all of Open Source maintainers and developers for all the work you’ve done. Without you, we wouldn’t be able to create amazing products. Probably we wouldn’t be able to do anything. This community is marvelous, you are marvelous.

Insights

Learn more about Community

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Oct 9Live Stream

React Native Conf 2025: React Foundation, Compiler 1.0 & Future of React Native

React Native Conf 2025 brought huge announcements: React Foundation under Linux Foundation, React Compiler 1.0 and Hermes v1. What’s next for React Native and newest React Features.

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Sep 25Live Stream

Live Dev Session: <Activity>, Expo SDK 54, Router v6, Lynx 3.4, TanStack Start

A packed week in the React ecosystem: React experiments with a new <Activity> component, Expo SDK 54 speeds up builds, Expo Router v6 adds native-like navigation, Lynx 3.4 ships inputs & dev tools, TanStack Start hits RC, and React Router previews Framework Mode.

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Sep 18Podcast

Core Contributor Summit 2025 Highlights

Core contributors from across the React Native ecosystem discuss stability, tooling, and the path to 1.0, from Flow to TypeScript, desktop apps, and how community fills the gaps left by Meta.

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Sep 11Live Stream

Live Dev Session: React Universe Conf, RN 1.0, Expo Updates & More

In Week 37 of our Live Dev Session we talked about React Universe Conf with guest Szymon, ranted about AI, explored what React Native 1.0 really means, reviewed Expo updates, and covered the latest moves in the React Native ecosystem.

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Sep 5Podcast

Crossing Paths of React And React Native Ecosystems

React and React Native: are the two ecosystems pulling together or apart? Let's discuss their evolution, similarities, differences, and community dynamics.

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Aug 20Podcast

We're Changing Into React Universe On Air

Here comes a new chapter for The React Native Show: we're becoming React Universe On Air!

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Jun 10Article

Apple Vision Pro: Insights From Conferences and Beyond

Explore key insights from introducing Apple Vision Pro at tech events. Discover its intuitive interface, immersive experiences, and the challenges faced.

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Mar 15Article

How to Make Your Open Source Project Repository Contributor Friendly

Check out 5 tips on making the repository of your Open Source project more contributor friendly for both new maintainers & users.

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Mar 1Article

React Native EU 2023 and a Glimpse Into Conference History

React Native EU is back for an on-site 2023 edition! Find out why it's worth attending our React Native conference and how it's evolved since 2017.

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Mar 30Article

Supporting Ukraine Through the "Tech to The Rescue" Project: UA SOS App

Learn about Callstack's commitment to the Tech To The Rescue project supporting Ukraine: UA SOS app.

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Mar 8Article

Women Who Make Waves in the React Native Community

On International Women’s Day we spoke to women who make waves as React and React Native developers. Check what they said about their tech careers.

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Nov 5Article

Events We Hold for You - Culture Powered by Callstack

When working at Callstack, you can join our unique initiatives. Find out more about our conferences, meetups, hackathons & discussion panels. Join our team!

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Mar 19Tutorial

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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Mar 12Tutorial

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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Mar 5Tutorial

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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Feb 24Tutorial

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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Feb 10Tutorial

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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Jan 29Tutorial

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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Jan 19Tutorial

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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Jan 9Tutorial

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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Dec 30Tutorial

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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Dec 22Tutorial

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.