Michał Pierzchała

Discover how we optimized Agent Device to reduce LLM token consumption by over 50% and speed up AI-driven mobile app automation.

Agent Device is a lightweight CLI for AI-driven mobile automation on iOS and Android, with structured snapshots and deterministic replay.

We're turning React Native optimization knowledge into agent-ready skills (JS, native, bundling) mapped to FPS and TTI, built from real-world production work

Seven major React Native releases in 2025, React Native turns 10, the New Architecture becomes the default, and 1.0 moves into view. A recap of 2025’s biggest RN updates.

Standard mobile testing tools fail for React Native TV apps due to D-pad navigation. This guide shows how to build custom helpers for React Native Testing Library that emit hardware key events and how to configure Appium for end-to-end testing on tvOS and Android TV.

A practical guide to fixing the "Unable to load script" error in React Native when the Android emulator can’t connect to Metro.

Rock is the new name for the React Native Enterprise Framework (RNEF). A solid foundation for enterprise-grade, cross-platform apps. Faster CI, build caching, iOS ad-hoc installs, and more.

Learn how to cache your React Native builds and store them on Amazon S3 or R2 to reuse across your team.

Add license acknowledgments to your React Native app with ease using React Native Legal-a zero-config tool for OSS compliance across iOS, Android, tvOS, and AndroidTV platforms.

Meet a React Native framework designed for enterprise apps, optimizing build reuse, CI speed & cloud integration while staying flexible and self-hosted.

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

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

Discover Reassure - an open source library for measuring performance regression of React and React Native components of your app.

Migrate seamlessly from native to React Native - greenfield, brownfield, and best practices covered!

We’re merging React Native Testing Library and Testing Library together! Check out what's the story behind that and how it will make your testing easier.

React Native Testing Library 2.0 is out now! Read the article and find out what's new. Check our migration guide.

Read about Michał Pierzchała's thoughts on a month spent with Recat Native Open Source Evangelists

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.

Discover how Rock cuts build times, streamlines CI, and simplifies large-scale app development for growing teams.

Join Callstack and Webpack experts as they discuss the most interesting tech announcements from the Next.js Conf 2022.

In this Coffee Talk Michał Pierzchała, Oskar Kwaśniewski, and Łukasz Chludziński comment on the results of the State of React Native survey. Check it out!

Explore Reassure, an Open Source tool for measuring performance regression in React Native apps.

Introducing Coffee Talks! Dive into the latest news in React and React Native with our hosts.

In this episode, Łukasz invites Oskar and Michał to discuss their experimental journey of bringing React Native to Apple Vision Pro and visionOS.

In April 2023, we enjoyed talking about performance optimization in the US. We went to San Francisco, Los Angeles and Detroit to meet some amazing folks from the React Native community - we loved the intense thought exchange there!

Join Michał Pierzchała and Abi Thiao as they discuss the most interesting talks at App.js Conf 2022 and other React and React Native news.

Explore the pros, cons, and lessons from gating access to open source libraries, plus insights on handling payments with tools like NPM Kiosk and Reassure.

The first episode of React Universe On Air (formerly known as The React Native Show) provides insights into React Native Testing Library. Mike and his guest give a quick glimpse into the very concept of Testing Library and tell the story behind React Native Testing Library.

Learn how to get started with Open Source, find the right project to contribute to, and explore top React Native libraries from the Callstack community.

April 2023 Callstack OSS Update: RFC for Expo Config Plugins, Re.Pack & Paper news.

Michał Pierzchała will speak at AI Coding Summit London 2026 about mobile QA agents for iOS and Android pull request workflows.

Join Callstack and Expo in San Francisco for practical talks on AI-native mobile development, Expo Agent, Cloud Agents and autonomous mobile QA.

Michał Pierzchała will present Automating Mobile QA with Cloud Agents at Ship London on 17 June 2026.

A discussion on Agent Device, AI-driven workflows, and testing mobile apps using simulators and accessibility data.

Learn how to run on-device LLMs in React Native using Vercel’s AI SDK from Michał Pierzchała's talk at DevAI by Data Science Summit.

Learn how React Native Harness bridges the gap between mocking and E2E testing: real device tests, full native access, Jest-style simplicity.

Learn how to integrate React Native into Android TV apps at the Vega Developer Meetup. Workshop, roadmap, and community talks, live in Munich.

Explore React Native’s past, present, and future with insights from Meta and Callstack on stability, new architecture, and enterprise-ready tooling.

Discover Rock by Callstack: the open, modular, self-hosted framework for React Native. Built to help teams scale, migrate, and deliver faster in the evolving React Native ecosystem.

Learn how to smoothly adopt React Native in your existing apps using Callstack’s Rock for easier setup, faster deployment, and seamless integration.

Learn how Callstack’s new React Native framework slashes CI times and simplifies enterprise-scale mobile development.

Join us in NYC or online for React Universe Meetup: tech talks, real-world insights, and networking with React Native devs. June 24, 2025.

Learn how to easily add React Native to your iOS and Android apps with a modern brownfield setup powered by Callstack’s open-source tooling.

Discover how to skip 90% of native builds in React Native CI using Rock. Includes a live demo and cost-saving insights from Expensify’s setup.

Missed the React Universe Meetup SF? Watch the livestream recording soon, talks on RN performance, optimization, and build-free workflows await.

Learn more about Callstack's Rock straight from its creators.

This is the Keynote talk presented at React Universe Conf 2024, the largest community conference that unites developers and thought leaders to explore trends, share insights, and push the boundaries of React and React Native.

Watch a webinar on optimizing React Native apps to learn the top 5 metrics every React Native team should track to improve performance, reduce load time, and boost user experience.

Learn how communication shapes your app development, from code to design. Discover React’s role and leverage Conway’s Law for success.

App developers shape code, but communication with others truly designs products. This talk explores how React and Conway’s law influence this process.

JavaScript powers a React Native journey on Apple Vision Pro, adapting to spatial apps and visionOS quirks for a unique dev experience.

Join us to learn how Re.Pack helps manage complexity in React Native apps, enables scalable teams, and boosts release processes.

We know what it takes to make React Native work for serious-scale applications. That’s why we created Rock, so enterprise teams can build with confidence, efficiency, and full control over their stack.

Developers often fix performance issues in React apps, but this is unsustainable and prone to regressions. Reassure, a testing library, helps spot problems before production, enhancing automated testing suites.

End-to-end tests are notoriously slow and costly, especially in mobile development. This talk introduces new tools and techniques to make E2E testing fast and efficient, so you can run tests on every pull request without draining CI resources.