Simek
Bartosz Kaszubowski
Full-Stack Developer
& UI/UX Designer
Open Source Advocate
About me
Passionate Full-Stack Developer and UI/UX Designer with a strong focus on creating innovative and user-friendly products, apps, services and tools. Member of the React Foundation and React Native Community, a long-term React Native Core Contributor and React Native Website maintainer. Co-creator and maintainer of the React Native Directory and all the tooling around it.
At Expo I was mainly responsible for developing and maintaining Expo Application Services, company styleguide, various developer tools and the documentation. In the past, I have also contributed to multiple Meta projects like Docusaurus and Infima. Currently I am working on multiple projects and contracts, including improving Lichess user interface and user experience for all chess fans around the world.
As an Open Source Advocate, I promote free and open software, niche projects and share knowledge within the community. I stay current with emerging industry trends, including AI and agentic workflows, while continuously expanding my skill set to help other maintainers and deliver thoughtful, tailored solutions to modern problems.
— Want to talk? Feel free to reach out via any listed above socials.
Main projects
A framework for building native applications using React
A searchable and filterable directory of React Native libraries.
The React Native website and docs
Nightly integration tests for React Native
♞ lichess.org: the forever free, adless and open source chess server ♞
An open-source framework for making universal native apps with React. Expo runs on Android, iOS, and the web.
GitHub Actions
Creates a comment inside Pull Request with the human-readable summary of changes to the Yarn lock file. Works with every Yarn version (classic and berry).
Creates a comment inside Pull Request with the human-readable summary of changes to the Bun lock file.
Developer Tools
OXC toolset pre-made configs + fetch CLI
Expo-inspired VS Code editor and syntax theme.
A CLI for submitting new entries to the React Native Directory
Find and install right packages for all of your React Native apps right from your VS Code.
Allow viewers to interact with your VS Code editor.
ESLint plugin integrating alex to flag potentially insensitive language in text files, comments and strings.