From brownfield to AI, from Polygen to Re.Pack

Hey! It’s Mike, CTO and Founder at Callstack, stepping in for this month’s edition. Welcome to 2025!

Let’s kick it off! Before we continue with React and React Native updates, let’s go over some important announcements.

Meet Callstack Incubator Team

At Callstack, we’re deeply committed to Open Source and moving React and React Native forward. That’s why, a few months ago, we established a full-time team to work on the hardest and most innovative challenges and opportunities in our community.

We call it Callstack Incubator.

The team consists of:

• Oskar Kwaśniewski (@o_kwasniewski)
• Mariusz Pasiński (@mani3xis)
• Robert Pasinski (@rob_pasinski)
• Michał Pierzchała (@thymikee)
• Piotr Drapich (@dratwas)
• Myself (@grabbou)

You can follow our work on GitHub, X, or… keep subscribing to this newsletter!

Join us on Discord!

One of our goals is to build in public, in short iterations. We’re doing all our work on Discord, inside dedicated channels.

If you’re looking for an easy way to get started contributing to React and/or React Native, you are welcome to join us, ask questions, and offer help.

We currently have over 8000 users, and we’re excited for you to join! Here’s the invite link.

New format

Our newsletter will now focus exclusively on important updates about what we’re cooking at Callstack and what to expect in the coming months! That includes updates from the Callstack Incubator team and all our engineers working on Open Source every day.

Each newsletter will be run by a different member of our Incubator team on a round-robin basis, starting with myself. I won’t outline its new structure—you will find that out by reading this issue!

For more general React and React Native updates, we advise you to subscribe to This Week In React by Sébastien Lorber. It is sent weekly and does a deep-dive into what’s hot in our fast-moving React world.

That said, let’s start with January 2025 updates!

Highlights

Early preview of Polygen

We released an early preview of Polygen—a library for running WebAssembly modules in React Native, statically, without interpretation.

If you want to learn more, you may want to check out our past live stream on Polygen, where Robert walks you through its internals and how to get started. Make sure to check out Polygen on GitHub and give it a star!  

Flows AI

We also continue our exploration of the AI space. This time around, we’re releasing Flows AI—a light-weight library for building AI agent workflows.

If you’re building applications with AI agents, you may also read Building AI Agent Workflows With Vercel’s AI SDK: A Practical Guide.

New release of React Native Bottom Tabs

The new release of React Native Bottom Tabs is out! Comes with a bunch of fixes for some of the edge cases reported by the community, and a lot of important changes under the hood.

In addition, you can read Solving Swift Modular Header Issues in React Native for Good by Oskar, where he talks about challenges he run across using Swift in this library.

RePack

We’re actively working on RePack, recently adding support for Expo Modules and new init experience.

Jack Herrington seems to really enjoy the latest features, you can learn more in his latest video on RePack. We have a lot coming up in the next weeks, so make sure to follow RePack on Twitter and GitHub.

React Native Framework

For the past couple of months, we’ve been working on a React Native framework, specifically for current users of React Native Community CLI. It is a spiritual successor of the CLI that brings massive improvements to infrastructure, including faster build times and more predictability.

We’re currently testing this in production with a few customers. We’re looking to release an early preview next month with interested developers.

React Native At Scale

We brought back the React Native At Scale series of our React Universe On Air podcast. In this series, we interview enterprises using React and React Native, from how it all started, to challenges they face everyday at scale.

Check out this and other episodes we have done this month too:

• React Universe On Air #47: Mobile Microfrontends With Zephyr Cloud and Re.Pack featuring Zack Chapple and Jakub Romańczyk
• React Universe On Air #46: Lessons from Shopify’s Migration to React Native with Mustafa Ali
• React Universe On Air #45: Universal React Native Apps with DOM & React Server Components featuring Evan Bacon

Ultimate Guide to React Native Optimization

We are working on a whole new Ultimate Guide to React Native Optimization.

While you’re waiting for the release, you should check other guides we have published in January.

• Incremental React Native Adoption Reimagined where we discuss client scenarios and real-world stories on adopting React Native in existing applications (hint: we’re integrating this approach in RNEF as well).
• React Native Performance Optimization with DMAIC where we talk about optimizing the performance of React Native applications with a methodology called DMAIC that helps us better understand the problem, define and narrow it down, and then fix it!

We’re in Tokyo!

In February, we’re heading to Tokyo for React Native Meetup #20 ft. Meta & Callstack (Feb 18) with me (Mike Grabowski) talking about building universal super apps with React and React Native.

React Universe CFP is starting soon!

Starting February 10th, we’re opening the Call for Papers for React Universe Conf 2025. We’re looking for all things full-stack and cross-platform with React and React Native.

If you’ve got something exciting, insightful, or game-changing to say, we’d love to have you on the stage. Check out the conference website for details.

Thank you for following along! I hope you like this new format! As always, we’re open to your feedback and tips for improvements.

Till next time!

Mike