Software Engineer

Maciej Jastrzębski

Maciej Jastrzębski

An expert in building native iOS and Android apps with years of experience. Passionate about creating well-architected, high-quality mobile applications and enabling dev teams to work efficiently. Maintainer of React Native Testing Library and Reassure OSS projects, with a strong focus on TypeScript, best practices, new architecture, testing, and performance. Enjoys traveling and capturing travel photography.

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What I’ve been shipping

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Article
6/24/2026

Writing Custom Renderers for React

Learn how React renderers work, why RNTL needed a new test renderer, and what it takes to connect React Reconciler to a host environment.
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Article
7/24/2024

Adding React Native to an Existing Flutter App

Discover how to integrate React Native into an existing Flutter app, leveraging platform views and setting up on both Android and iOS.
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Article
8/5/2020

React Native Testing Library With Redux

In this article, we discuss how Redux can be helpful in proceeding tests with React Native Testing Library and how can you benefit from this solution.
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podcast
7/17/2024

What's New in Reassure 1.0

Find out how to monitor React and React Native performance better than ever before with Reassure's new features.
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podcast
7/28/2022

Reassure - Open Source Tool Measuring Performance Regression

Explore Reassure, an Open Source tool for measuring performance regression in React Native apps.
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podcast
3/28/2024

React Native Performance in 2024: Challenges, Solutions, Forecasts

Join us as we explore the latest developments in React Native performance optimization with experts from Expo and Callstack.
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Event
Webinar
Webinar
11/5/2025

Scaling React Native at Zalando: How Brownfield Migration Paid Off

Discover how Zalando scaled React Native across a massive e-commerce app, from internal buy-in to brownfield rollout, and what they learned.
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