In this episode of React Universe On Air (formerly known as The React Native Show Podcast), our host, Mike Grabowski, and his guests: 
- Eloy Durán, a Software Engineer at Microsoft (https://twitter.com/alloy)
- and Xuan Huang, a Software Engineer at Facebook (https://twitter.com/Huxpro)
talk about the latest React Native 0.64 release which comes with Hermes support for iOS!

It’s a great opportunity to know the details of this major update to React Native 0.64 because Mike, Eloy and Xuan worked together on bringing Hermes to iOS!

In the first part of the podcast, our experts focus on the following topics:
- Hermes improvements to React Native apps in terms of three metrics: Time To Interactive (TTI), Application Size (APK), Memory consumption
- The “magic” behind Hermes - “Bytecode Precompilation” a.k.a. AOT
- The difference between AOT and JIT
- JIT JS engine pipeline vs Hermes pipeline
- The Hermes roadmap and plans for further improvements

Later on, Mike and his guests talk about the story behind bringing Hermes to React Native MacOS and take a quick look into the future of this major update.

In this part, they cover the following topics:
- What was the motivation behind adding support for Hermes on MacOS? Any plans for RN Windows?
- Were there any attempts to bring Chakra to run on macOS, to say, provide more unified experience across desktop platforms?
- On Apple devices, unlike Android ones, there was always less of performance and memory related issues when it comes to running React Native applications. What would be the selling point of Hermes in such a case?

This and much more awaits you in the Episode #5 of The React Native Show!

Don’t forget to push the Subscribe button and share this video on your social media. More episodes are coming soon!

Check out more episodes of The React Native Show
https://callstack.com/podcast-react-native-show?utm_campaign=Hermes_MB&utm_source=soundcloud&utm_medium=social&utm_content=hermes_podcast

Read more about Hermes on iOS

1. Bringing Hermes to iOS in React Native 0.64
https://callstack.com/blog/bringing-hermes-to-ios-in-react-native/?utm_campaign=Hermes_MB&utm_source=soundcloud&utm_medium=social&utm_content=hermes_podcast

2. Hermes Performance on iOS
https://callstack.com/blog/hermes-performance-on-ios/?utm_campaign=Hermes_MB&utm_source=soundcloud&utm_medium=social&utm_content=hermes_podcast

The React Native Show Podcast - Episode 5: "React Native 0.64 with Hermes for iOS"

React Native 0.64 with Hermes for iOS | React Universe On Air #5

Eighteen TV platforms, one codebase—what could possibly go wrong? Tune in to find out how to tackle the technical and UX challenges of building for Android TV, Apple TV, Fire TV, Tizen, and more—all with React Native!

In the 49th episode of React Universe On Air, Łukasz Chludziński (https://x.com/lukasz_app) teams up with Michael Khirallah (https://x.com/mkralla11), Senior Director of Engineering at DIRECTV, and Chris Trag (https://x.com/chris_trag), Developer Evangelist at Amazon, to discuss why cross-platform development is not just a time-saver but also a way to deliver a consistent user experience.

You know that at Callstack, we’re all about performance—and with devices like Samsung’s Tizen TVs released in 2017 (running Chromium 47!), performance is a serious concern. That’s why we asked our guests to share real-world techniques for optimizing TV apps, from architectural choices to strategies that avoid unnecessary performance hits on newer devices.

The complexity of TV app development doesn’t stop at coding, though. Our host and guests know it all to well, so they couldn’t help but discuss how they balance unit, integration, automation, and manual testing, leveraging tools like AWS Device Farm and custom-built frameworks to ensure stability across all supported platforms. What’s in it for you? Tips on automating QA without compromising thoroughness and why manual testing remains crucial for end-user experience.

Want to get started with React Native TV app development? Download our guide 📖https://hubs.li/Q038xx4l0 

Check out episode resources on our website 🧠 https://hubs.li/Q038xx3k0 
Check out other episodes of our podcast 🎧 https://hubs.li/Q038kRpf0 

Become a speaker at React Universe Conf 2025 🎟 https://sessionize.com/react-universe-conf-2025/ 
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Follow us on X 🐦 https://twitter.com/callstackio


Multiple TV Platforms, One Codebase: React Native TV App Development | React Universe On Air #49

Ever wondered why TypeScript works so well with JavaScript libraries?  It’s thanks to Definitely Typed, a project that helps developers use these libraries with type safety and autocompletion 🚀

In this Coffee Talk episode of React Universe On Air, Mike Grabowski https://x.com/grabbou chats with Boris Yankov https://x.com/borisyankov, the creator and maintainer of Definitely Typed, to uncover its story 📚

🟣 TypeScript's Beginnings: Boris revisits 2012, discussing initial challenges and contributions 
🟣 Growth to Open Source Giant: From a personal project to a community powerhouse, aided by Microsoft 
🟣 TypeScript vs. Flow: Discover why TypeScript thrived with robust type definitions 
🟣 Functionality: How Definitely Typed integrates with NPM and TypeScript tooling 
🟣 Open-Source Dynamics: Insights into collaboration without strict leadership 
🟣 Top TypeScript Features: Boris and Mike's favorites, plus development tips 

Now, let’s hear from you! Have you ever contributed to Definitely Typed? If so, what library did you add types for and what challenges did you face? Share your experience to inspire new contributors! 🚀

Check out episode resources on our website 🧠 https://bit.ly/4jdRoSD 
Check out other episodes of our podcast 🎧 https://bit.ly/4hzoScR 

Get your React Universe Conf 2025 tickets 🎟 https://hubs.li/Q03d4Hll0 
Sign up for Callstack newsletter ✉️ ​​https://bit.ly/4iVScLz 
Follow us on X 🐦 https://twitter.com/callstackio

How Definitely Typed Changed TypeScript Forever | React Universe On Air #26

Tanner Linsley joins React Universe On Air to unpack the evolution of the TanStack ecosystem—from React Table and React Query to TanStack Router and the newest addition to the family, TanStack Start ✨

What started as internal tooling for Nozzle became a suite of libraries that shaped how developers think about server state, routing, and full-stack React apps. In this episode, Tanner shares the technical decisions behind building framework-agnostic, headless tools—and explains why client-side architecture still matters in a server-first world.

You’ll also hear why TanStack Start isn’t just another full-stack framework, how React Server Components could be treated like server state, and what’s coming next for TanStack Router.

If you're building React apps at scale or deciding how to modernize your frontend stack, don’t skip this one!

Check out episode resources on our website 🧠 https://bit.ly/41Z876l
Check out other episodes of our podcast 🎧 https://bit.ly/3XIHBeU

Get your React Universe Conf 2025 tickets 🎟 https://hubs.li/Q03g5cLM0
Sign up for Callstack newsletter ✉️  https://bit.ly/4lwS7QP
Follow us on X 🐦 https://twitter.com/callstackio

Chapters

00:00 Welcome to the React Universe
00:00 Introduction to Open Source and Server State
01:15 Meet our guest: Tanner Linsley
02:19 How Tanner got into programming
04:06 Early programming days when there was no React yet
05:41 Cross-platform beginnings
07:40 Open Source contributions
09:24 Working on Chart.js
14:12 React Table at Nozzle
16:58 How React Static started
20:53 React Query taking shape
27:53 Community reactions to React Query
33:18 Framework agnostic approach
36:26 Cross-platform frameworks comparison
37:56 Headless, type safety, and no dependencies
46:22 TanStack Router
01:00:59 TanStack Start
01:11:06 React Server Components
01:18:51 Wrap-up
01:20:29 React Universe Conf Speakers Announcement

TanStack Ecosystem with Tanner Linsley: React Query to TanStack Start | React Universe On Air #50

Is rewriting your native app really the only way to go cross-platform?

In this Coffee Talk episode, we explore how React Native Brownfield offers a smarter path forward.

Łukasz Chludziński invites Oskar Kwaśniewski and Burak Güner—who work directly on React Native Core and brownfield tooling—to discuss how recent advances in React Native have made brownfield integration far more viable, stable, and scalable.

You’ll learn:
➡️ Why brownfield isn’t what it used to be (goodbye, brittle bridging)
➡️ How `RootViewFactory` and `ReactNativeFactory` APIs simplify setup
➡️ What’s new in React Native Brownfield 1.0.0
➡️ How to keep your architecture clean while integrating React Native
➡️ What this means for modern native stacks like SwiftUI, Jetpack Compose—and future-facing platforms like visionOS

Whether you’re maintaining a legacy app or building for what's next, this episode gives you a blueprint for hybrid success.

Explore React Native Brownfield 🙌 https://github.com/callstack/react-native-brownfield
Check out episode resources on our website 📚 https://bit.ly/3ESW3Lf
Catch more React Universe On Air episodes 🎧 https://bit.ly/44A0q8q

Get your React Universe Conf 2025 tickets 🎟 https://hubs.li/Q03l-47N0
Sign up for our newsletter ✉️ https://bit.ly/3H2xsE6
Follow us on X 🐦 https://x.com/callstackio    

Timestamps
00:00 Welcome to the React Universe
02:00 Meet our guests: Oskar & Burak
02:50 Let’s talk brownfield app development
03:37 Craziest brownfield setups our guests have seen
08:19 Greenfield vs. brownfield React Native
14:14 How we used to approach brownfield development
18:20 Callstack’s React Native Brownfield
23:30 RootView Factory & React Native Factory
28:50 New Features in React Native Brownfield 1.0
35:35 Sharing data between native and JavaScript
41:00 How about using different React Native versions
43:30  Cost of complexity
47:00 Learn more and get in touch with our guests

You Don’t Need a Rewrite, You Need React Native Brownfield | React Universe On Air Coffee Talk #27

What if you could skip most native builds—and still ship confidently? In this episode of React Universe On Air, we explore how the React Native Enterprise Framework (RNEF) helps large teams dramatically reduce build times and streamline development at scale.

Our guest Michał Pierzchała, Principal Engineer at Callstack, shares how RNEF was built to solve real-world bottlenecks in enterprise React Native projects. Alongside him, Łukasz Chludziński discusses his experience testing the framework in a live production environment, where build times dropped from 35 minutes to just 3.

What you'll learn:
- How RNEF slashes native build times with CI-based caching
- Ways to adopt the framework incrementally—no full rewrite required
- How brownfield support lets you drop React Native into native apps easily
- What makes RNEF different from Expo and Community CLI
- Real-world savings and improved developer-QA workflows

Check out episode resources on our website 📚 https://clstk.com/4e5OL3W 
Explore React Native Enterprise Framework ✨ https://clstk.com/4kAt7ap
Catch more React Universe On Air episodes 🎧 https://clstk.com/3SJRk1G
Get 20x faster builds on your CI in less than a week with our help 👉 https://clstk.com/3ZWJ9Tq

Sign up for our New York meetup in June 2025 👉 https://clstk.com/4kEyG7C
Follow us on X 🐦 https://x.com/callstackio

00:00 Welcome to the React Universe
01:07 Host & guest introductions
02:40 Project overview: React Native Enterprise Framework
04:04 Challenges in large repositories
04:50 Testing and build time optimization
07:31 Building RNEF on a real-life use case
12:37 Integrating RNEF POC to the project
15:00 Incremental adoption mindset
21:42 What it all has to do with React Native Community CLI
26:05 Optimizing build process with smart caching
44:06 Seamless collaboration between devs & QA
47:28 Brownfield projects with RNEF
55:50 Where RNEF stands in the ecosystem
59:08 What does it mean to be a React Native framework?

From 30min to 3min Build Times With React Native Enterprise Framework

Should you be afraid of monorepos? Not with Nx. Tune in and learn how to scale apps without scaling pain.

In this episode of React Universe On Air, Łukasz Chludziński chats with Jordan Powell from Nx to explore what it really takes to build and manage a monorepo at scale. From dependency graphs to distributed CI tasks, they break down how Nx helps teams stay fast, focused, and frustration-free. Whether you're just getting started with Yarn Workspaces or running into CI bottlenecks, this episode gives you the strategies and context to go further with less overhead.

Key learnings

➡️ The difference between monorepos and monoliths
➡️ How Nx graphs improve selective builds and testing
➡️ What “ownership rules” mean for large codebases
➡️ How distributed task execution saves time in CI
➡️ Why better DX equals better business outcomes
➡️ Real-world patterns for React Native and full-stack monorepos

Catch more React Universe On Air episodes 🎧 https://clstk.com/44Bj51X
Get your React Universe Conf 2025 tickets 🎟 https://clstk.com/4nFqTZ1
Sign up for our newsletter ✉️ https://clstk.com/3TrnIGH
Follow us on X 🐦 https://x.com/callstacki

00:00 Welcome to the React Universe
00:42 Meet Jordan Powell from Nx
02:42 The joy and pain of testing
04:03 Understanding monorepos
06:52 The origins of Nx
09:41 Developer experience and its business impact
12:10 Nx vs. other tooling and a closer look at its features
21:07 Getting started with Nx
25:27 Collaborating on projects
28:00 Assigning ownership and scoping projects
29:30 Managing dependencies in a monorepo
31:16 Handling multiple framework versions and migrations
32:40 Real-world examples of large-scale monorepos
36:10 Distributed task execution with Nx Cloud
39:08 Efficient testing in a monorepo
42:55 The Future of Nx with AI integration
47:27 Conclusion and final thoughts

Monorepo Architecture with Nx

Many React Native apps ship without full observability. The result? Blind spots in performance, crashes, and user behavior once your app is in the wild.

In this episode of React Universe On Air, Łukasz Chludziński sits down with Jonathan Munz (Senior Software Engineer at Embrace) and Adam Horodyski (React Native Expert at Callstack) to unpack how OpenTelemetry can bring structure and clarity to mobile monitoring.

They break down why mobile observability is harder than observability on backend, what the OTLP protocol enables, and how to instrument React Native apps without locking into a single vendor. You’ll also hear how community-driven tooling like React Native OpenTelemetry and the Embrace React Native SDK can simplify setup and improve data portability.

You’ll learn:
➡️ How observability and OpenTelemetry work together
➡️ The 3 core OpenTelemetry signal types for mobile
➡️ Why mobile instrumentation is more complex than backend telemetry
➡️ How OTLP improves interoperability between tools
➡️ Where auto-instrumentation is still missing in React Native
➡️ The role of Embrace and open-source libraries in reducing setup overhead

Check out episode resources on our website 📚 https://clstk.com/4104nAF
Catch more React Universe On Air episodes 🎧 https://clstk.com/45EWnYe
Monitor what matters in your React Native app with Callstack’s help 🤝 https://clstk.com/3HoM3KI

Sign up for our newsletter ✉️ https://www.callstack.com/newsletter
Follow us on X 🐦 https://x.com/callstackio

Chapters
00:00 Welcome to the React Universe
01:07 Meet our guests
03:07 Defining observability and OpenTelemetry
04:32 Signals in observability
11:57 Challenges with observability in React & React Native
16:04 Standardization and OpenTelemetry protocol
18:08 Embrace and Open Telemetry
21:29 Future of OpenTelemetry in mobile
27:23 Exploring React Native OpenTelemetry
29:54 Community involvement in OpenTelemetry
37:34 Real observability in React Native
46:41 Future of React Native observability
50:40 Hey, listeners, here’s what we want you to do
54:46 Conclusion and final thoughts

Observability & OpenTelemetry in React Native

What really happens when React Native’s core contributors gather behind closed doors?

In this episode of React Universe On Air, recorded live at React Universe Conf 2025, host Łukasz Chludziński sits down with Joel Arvidsson, Jay Meistrich, and Thibault Malbranche to unpack the hottest debates and wisest insights from the Core Contributor Summit.

They dive into:
➡️ How the cooperation between consultancies, big organizations like Meta or Microsoft, and OSS contributors looks like
➡️ 2025 as the “year of stability” for React Native
➡️ The promise (and pain) of React Native for desktop apps
➡️ Flipper’s decline and new community-driven DevTools
➡️ Whether React Native 1.0 is just a marketing label or a true milestone
➡️ How agencies and individuals balance open source with client work
➡️ Practical advice for engineers who want to contribute and join the conversation

Chapters:
00:00 Welcome to the React Universe
01:21 Meet our guests: Thibault Malbranche, Joel Arvidsson, Jay Meistrich
02:33 What is Core Contributor Summit
04:02 Meta vs. community usage of React Native
07:19 Year of stability & tooling challenges
09:00 Surprise session: React Native for Desktop
16:10 Concrete outcomes vs. planting seeds
21:02 Open Source dynamics & collaboration
27:30 React Native 1.0
33:45 Future directions & getting involved
36:50 Final thoughts

Catch more React Universe On Air episodes 🎧 https://clstk.com/423vF9D
Sign up for our newsletter ✉️ https://clstk.com/3Kb23kM
Follow us on X 🐦 https://x.com/callstackio

Core Contributor Summit 2025 Highlights | Coffee Talk

The NFL runs on tight deadlines. Every kickoff and Super Bowl demands that millions of fans get flawless live video, stats, and fantasy features, whether they’re on iPhones, Xboxes, or connected TVs.

In this episode of React Universe On Air, Mike Grabowski talks with Michael Blanchard (Director of Engineering at the NFL), about how React Native became the backbone of this high-pressure, multi-platform ecosystem.

Michael shares his journey from web engineer to leading NFL’s engineering teams across nfl.com, three mobile apps, a cross-platform video player, and a suite of connected TV apps. Together with Mike, he explores the NFL’s migration strategy, the transition from Haul/Webpack to Metro and Expo, and the cultural shifts that helped merge web and native engineers into one collaborative team.

You’ll learn:
➡️ Why the NFL went full Greenfield (twice)
➡️ How NFL+ shaped their second rewrite
➡️ Lessons from moving from Haul/Webpack to Metro
➡️ How Expo SDKs gradually replaced community libraries
➡️ How GitHub Actions + EAS Build reshaped their CI/CD pipeline
➡️ Strategies for handling 20–30 PRs daily in a monorepo
➡️ How React Native powers mobile, web, and multiple connected TVs
➡️ What cultural shifts enabled true cross-platform collaboration

Catch more React Universe On Air episodes 🎧 https://clstk.com/4gp8Cw5
Sign up for our newsletter ✉️ https://clstk.com/4mfmRof
Follow us on X 🐦 https://x.com/callstackio

Chapters: 
00:00 Welcome to the React Universe
01:35 Meet Michael Blanchard from NFL
03:03 NFL's digital presence and platforms
04:24 React Native in NFL's mobile apps
08:32 How React spread across all platforms
11:47 Collaboration between web and native teams
18:11 Technical decisions regarding different platforms
23:48 V2 of NFL's flagship app
25:14 Choosing migration strategy
30:10 Maintaining more product versions
34:33 Adopting Expo
42:10 Modernizing CI/CD
46:48 Team structure and workflow at NFL
53:29 Final thoughts

React Native at Scale With NFL

It’s a practical, developer‑focused look at the early days of React Native on VR: what works today, what’s different from mobile, and why so many app ideas translate better than you might expect.

Chapters:
00:00 Introduction to React Native on Meta Quest
01:10 Meet the guests: Jan Jaworski and Ram N
01:28 Ram’s background and experience
04:10 Jan’s background and experience
06:09 Exploring React Native on Meta Quest
07:09 How Meta Quest started
11:00 Getting started with React Native on Meta Quest
14:30 Betting on AOSP
17:00 First-mover advantage and developer opportunities
21:32 Differences between mobile and VR
24:45 Running Expo projects on the headset
25:28 React Native on Meta Quest, now for real
27:27 Starting a React Native project on Meta Quest
28:49 Developing and debugging on Meta Quest
30:19 Do you need a headset or an emulator?
31:57 Virtual Reality Development Experience
38:09 AI tooling
40:02 Meta Horizon Start Developer Competition
45:02 Conclusion and final thoughts

Taking React Native Into VR on Meta Quest React Universe On Air

React Universe On Air is your go-to podcast about building cross-platform apps with React and React Native, featuring practical lessons, forward-looking ideas, and talks with industry leaders.

React Native 0.64 with Hermes for iOS | React Universe On Air #5

React Universe On Air

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