Hey!
It’s Michał again, stepping into March’s edition of this newsletter. This time we celebrate React Native's 10th anniversary, ship a new library to generate OSS licenses, and focus on performance as we’ve just released a new Ultimate Guide to React Native Optimization ebook. Let’s get right to it!
Community Highlights
Before we get to Callstack updates, take a look at some key updates in the React Universe from the last month:
- React Native was open-sourced 10 years ago—It’s been a wild ride, which we’re super happy to take. The technology matured from startups and scale-ups being early adopters to enterprises catching up on our favorite cross-platform tech.
- React Native 0.79 golden release candidate—Expect stable release next week. This is the version where we say goodbye to built-in JavaScriptCore, which you can still use with a library we’ve built.
- Standalone Worklets RFC—After years being a core part of Reanimated and tightly coupled to it, the team now plans to extract it to a separate library so that anyone could run JavaScript on any thread (not only UI thread).
- Create React Native Library supports Nitro Modules—The library that Callstack built and maintains now supports creating libraries using Nitro, so you can build fast libraries even faster.
- Lynx Roadmap for 2025—Clear release schedule, desktop support for Windows, macOS, and OpenHarmony, new native capabilities, UI elements, and improved tooling
Callstack Incubator Highlights
Here are the updates from our full-time Open Source team.
The Ultimate Guide To React Native Optimization 2025
We’ve been working hard to deliver you a refreshed—and the best ever—version of our classic guide! It’s rewritten from scratch by our small team with guest appearances from Callstack experts.
It features “how to’s” related to profiling, memory management, threading, app startup timeline, and some more grouped in JavaScript, Native, and Bundling categories. On top of these guides, which we hope will teach you the “how” of performance optimization, we’ve added the “what” – best practices we implement in our client’s apps that we kept short-form so you can adopt them quickly in your apps, too.
Download your copy here. It’s free, as always.
Oh, and did I mention you can read it on your Kindle or other EPUB reader instead of only PDF? So what are you waiting for?
We’ll be holding a React Universe Meetup in San Francisco on April 24, together with Expensify. We’ll bring some printed copies of the guide. Make sure to come by and get one! If you can’t be there in person, we’ll stream it online, but no book then 😢
React Native Legal
We’ve introduced a new package for automagically generating license acknowledgments for your React Native app. You can use it in Expo apps with “react-native-legal” config plugin or in Community CLI projects with “legal-generate” command. It works with iOS, Android, tvOS and AndroidTV.
Giving acknowledgments to all awesome open-source dependencies you use in your apps is not only a privilege, but, in many cases, a legal requirement. Instead of manually scrubbing through each and every dependency, our react-native-legal package will do it for you.
React Native Bottom Tabs v0.9.0
Oskar released a new version of the Bottom Tabs library that includes freezeOnBlur integration, fixes for TV platforms, and the removal of the now-unnecessary ignoresTopSafeArea prop.
If you missed it, Oskar also wrote a guest post on the React Navigation blog, covering his library and how to integrate it with React Navigation.
Is this app using React Native?
Verifying what apps use React Native and whether the one we’re particularly interested in does do, it still not as easy as it could be. I’ve tried that myself a few times, and it’s either a bunch of manual work downloading APKs from some mirroring services or writing a bunch of scripts to handle that automatically.
Szymon has an interesting side project that allows checking whether an app uses React Native by simply searching for it. Give him some encouragement so he releases it!
Rock
We’ve been busy doing webinars and giving talks, but we didn’t forget about shipping new functionality! Internally, we released a work-in-progress documentation, merged initial brownfield instructions support for iOS and Android (this one still needs some polish), and are onboarding more early adopters and figuring out edge cases, so you won’t have to once we reach the public release milestone. Will it happen at the React Universe Meetup in SF this month? Maybe 👀
Here's a part of the documentation on how to add the framework to an existing iOS app:
Polygen and team hacking in Barcelona
Robert and our friend Kræn Hansen gave a talk about Polygen—our library for running WebAssembly modules in React Native apps without runtime overhead—in Barcelona at the WASM.IO 2025 conference.
We took it as an opportunity for a team to get together and spend some time hacking on a top-secret project we hope to share with you soon.
In addition to all the releases and retreats, we’ve been working hard on some content, too!
Blog
- Why Knowing Your App’s Bundle Contents Matters for React Native Performance by Szymon Chmal
- We’re Building a New React Native Framework by Michał Pierzchała
- Local LLMs on Mobile Are a Gimmick—For Now by Kewin Wereszczyński
React Universe On Air podcast
- React Universe On Air Coffee Talk #26 How Definitely Typed Changed TypeScript Forever featuring Boris Yankov, the repository’s creator and long-time maintainer.
Webinars & live streams
- Using React Native in Existing Apps for Faster Cross-Platform Features—Mike and Burak walked through exactly how to embed React Native into native apps, without killing performance or team velocity.
- The Ultimate Dev Machine Setup: Experts’ Must-Haves & Community Picks—Łukasz, Ola, and Szymon went live and tried to turn a factory-reset laptop into a fully optimized React, React Native and web dev machine. Watch the recording to find out how it went and check out the key takeaways.
Coming soon
We're also cooking a few things that you should watch out for:
- Node API: We’re progressing on an exciting yet still experimental project that will allow us to use Node add-ons in React Native without much overhead and much more. Keep your fingers crossed that Mario and Kræn will ship something on this initiative soon!
- React Native Brownfield: Now that Oskar delivered the first release candidates for the library, we’re looking into integrating it directly with Enterprise Framework to provide a best-in-class experience when adding React Native to existing native apps.
April events are coming in hot
We’ve got some exciting events lined up this April. Whether you're in Poland, the US, or anywhere else in the React Universe, there’s a way to join us.
React Universe Meetup with Expensify, San Francisco
📆 April 24, 2025, 5:30–9:00 PM PDT
📌 Expensify Office, 88 Kearny St, 16th Floor, San Francisco, CA 94108, US
We’re teaming up with Expensify to bring you an evening packed with top-tier tech talks, real-world insights, and... a pretty major announcement from Callstack. Whether you’re joining us IRL or tuning in online, here’s a taste of what’s coming:
- Native Apps Without a Build Step—yours truly
- User-Focused Performance Tracking—Tim Golen, Director of Engineering at Expensify
- A special announcement from Callstack
- Networking and a giveaway of our Ultimate Guide to React Native Optimization 2025
React Universe Meetup, Wrocław
📆 April 16, 2025, 18:00–21:00 CET
📌 Callstack Office, Wrocław, Poland
Hosted by the Callstack Incubator team, this Wrocław edition of our React Universe Meetup is a perfect blend of community, knowledge sharing, and good vibes (yes, pizza and drinks included).
Expect three insightful talks—including a guest speaker—and an easygoing networking session with some of the brightest minds in React and React Native. Register here.
React Universe Conf 2025: New Speaker + Workshops + Early Bird Countdown
React Universe Conf 2025: new speaker, workshops, early bird discount
Some big updates on the conference front:
- Xuan Huang is joining the speaker lineup! We’re thrilled to have him on board.
- Workshops announced! First up: React Native Performance, happening on September 2, 2025 (you can already book your workshop seat).
- Early Bird tickets are almost gone, grab yours before April 30.
- Group Discounts: Planning to come as a crew? Use the code RUC25Teams for 15% off when buying 4+ tickets.
We can’t wait to see you there—whether it’s across the ocean or just down the street!
Thanks for going through our updates. Stay tuned for more in April, and if you can’t wait already, follow us on your favorite media channels.
Cheers,
Michał
