Software Engineer

Mariusz Pasiński

Mariusz Pasiński

Low-level C++ developer and former game developer who became passionate about mobile app development. Enthusiastic about hacking, optimization, and continuous learning, he sees software development as a form of craftsmanship. Created an app that renders the entire Vice City in just one draw call and enjoys applying minimalism to almost everything.

Low-level C++ developer and former game developer who became passionate about mobile app development. Enthusiastic about hacking, optimization, and continuous learning, he sees software development as a form of craftsmanship.

Created an app that renders the entire Vice City in just one draw call and enjoys applying minimalism to almost everything.

What I’ve been shipping

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Article
7/24/2025

Exploring Fibers: Cooperative Multitasking and Lock-Free Task Execution

Explore how fibers enable lightweight, cooperative multitasking. This guide walks through building a simple scheduler, managing task dependencies without locks, and using Tracy to visualize performance.
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Live Stream
7/15/2025

Build High-Performance Modules in React Native With Node-API

Discover how to build and share native code in React Native using Node-API: faster builds, runtime agnostic, and language flexible.
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Article
7/10/2025

Announcing Node-API Support for React Native

We are bringing Node-API to React Native to simplify native module development. Learn how this ABI-stable, cross-runtime system can unlock faster builds, better maintainability, and broader ecosystem interoperability.
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Article
5/21/2025

Multithreading Isn’t Free: Performance Pitfalls Visualized

Learn how to profile and optimize multithreaded apps. Discover why more threads don’t always mean faster results and how bad thread contention really is.
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Article
4/11/2025

Profiling React Native Internals with Tracy for Peak Performance

Learn how to profile React Native internals with Tracy to uncover bottlenecks, optimize performance, and gain deep insights into your app’s native behavior.
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Article
2/11/2025

How to Profile Native Code in React Native Using Tracy

Learn how to profile your code to uncover performance bottlenecks and optimize speed using the right tools and relevant debugging strategies.
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Live Stream
2/3/2025

React Native WebAssembly Release Walkthrough

Join us for a deep dive into Polygen: Callstack Incubator's breakthrough in React Native development!
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Podcast
9/24/2024

How to Get Started With 3D in React

Learn how to implement 3D in React apps, learn more about top libraries like React Three Fiber, and dive into WebGPU's future.
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Podcast
5/31/2024

Stepping Into New Dimension With React Native VisionOS

Try immersing yourself in the React Universe with React Native visionOS! Listen about the latest changes in the framework & watch a 3D app demo.

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Build the AI-native React Native future

Work with engineers who contribute to the ecosystem and turn new technology into real products. At Callstack, AI is part of how we build, learn, and ship software.