Meet the team of

CALLSTACK experts

We are a great team of trusted React and React Native experts - passionate about what we do!

React Universe

Meet our team

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Team member
Callstack astronaut

React Native Developer at Callstack. Currently, he’s strengthening his knowledge of native development and making some OSS contributions. Constantly seeking for new and exciting tech products to play around with. During his free time, he enjoys going to the gym, and playing video games.

Oskar Kwaśniewski
Software Engineer
Team member
Callstack astronaut

Seasoned scrum master, project manager, and business analyst. Happy to share his experiences collected over 12 years in IT across Poland, Switzerland, and Germany - be it through 1:1 mentoring, on-the-job coaching, or through training/lecture setup. Life-long learner, achiever, relator, believer, and analytical mind leveraging a no-nonsense approach. Passionate system thinker, jack of all trades - master of some. Origami fan, rock'n'roll dancer, student of genetics and rare diseases.

Patryk Czmochowski
IT Project Manager
Team member
Callstack astronaut

An experienced React developer with passion for sport-related apps. React Native enthusiast, meticulously crafting best user experiences in mobile space. Her strong attention to details is backed up by solid technical skills. Interested in design fields and state management of mobile apps. When Paulina turns off her laptop after work, most likely she's playing tennis or riding MTB.

Paulina Chmielewska
Software Engineer
Team member
Callstack astronaut

Started making mobile apps 12 years ago as a native iOS developer and gradually moved to React Native around late 2016, which has become the main focus since. Passionate about the possibilities opened to society through mobile devices being carried and used every day. Currently interested in bringing web3 and decentralized services to life via apps. Privately a self- development book mole and long walks' enthusiast.

Paweł Kata
Software Engineer
Team member
Callstack astronaut

Software developer passionate about JavaScript, always striving for a deeper understanding of it. Started his programming journey from React for Web, and he's now diving into mobile with React Native. Privately - code purist, minimalist design enthusiast and amateur tennis player.

Paweł Szymański
Software Engineer
Team member
Callstack astronaut

Experienced Business Analyst with Business Intelligence background. Maintainer of good agile practices within projects. Big Data Analysis expert. Not afraid of any challenges, with personal motto:" Keep calm and keep being agile".  Establishing service management infrastructure in Poland - Global Network and Account Management division in one of top Swiss Bank. Renaissance soul - love to express myself with art, preparing top chef meals, meditation & music.

Paweł Ulanowski
Business Analyst
Team member
Callstack astronaut

React Native developer with good problem solving skills, always eager to help others and learn from them. Passionate about building robust apps that follow the best standards in the industry. His field of interest is Research & Development. After work, Pedro enjoys playing video games.

Pedro Guerreiro
Software Engineer
Team member
Callstack astronaut

A RN Expert working all across the stack, always glad to help you manage the technical aspect of a project and lead your team to success. Experienced in the native mobile and Web app development. Always looking forward to exploring the new cross-platform technologies from React Native to Kotlin/Native. Mentor in the field of Native Development at Callstack.

Piotr Drapich
Expert Software Engineer
Team member
Callstack astronaut

Software Developer with years of experience in building web applications using React and Angular. Passionate about building well-designed, practical apps along with writing well-architected and readable code.Loving to dive into the graphical part of app architecture. Besides his main work at Callstack, Piotr is also a bartender on the weekends!

Piotr Fijałkiewicz
Software Engineer
Team member
Callstack astronaut

A senior software developer, who started his journey with mobile apps. Currently focused on brownfield and native development in the React Native apps. React Native Pager View core contributor and maintainer. When not coding, he spends his free time on the dancefloor.

Piotr Trocki
Software Engineer
Team member
Callstack astronaut

A self-taught developer who started from automation in an automotive industry, then transitioned to front-end, and some time ago moved into mobile development. Currently, working mostly in React Native. As you can see, he likes learning new technologies. Passionate about building simple and minimalist UI interfaces. In his free time, Przemek teaches kids programming.

Przemysław Gawron
Software Engineer
Team member
Callstack astronaut

JavaScript developer specialising in frontend and mobile development, but also fully capable of working on the backend-side of apps. Maintainer of the Re.Pack OSS library.

Rafał Zakrzewski
Software Engineer
Team member
Callstack astronaut

JavaScript developer by day, polyglot programmer by night. Experienced in web app development with full-stack background. Loves to learn new programming languages, paradigms & technologies and deep-dive to understand how they work under the hood. A big fan of clean code and functional programming. In his free time he likes to take photographs, play games and work on open-source projects.

Robert Pasiński
Software Engineer
Team member
Callstack astronaut

React Native and Web developer who specializes in JavaScript, TypeScript, and all things frontend related. Satya has created and maintained many open source libraries for React Native & Web such as React Navigation, React Native Paper, React Native Builder Bob, Linaria etc.Creator of React Navigation 5 and Linaria.When not coding, Satya loves cooking or playing video games.

Satyajit Sahoo
Expert Software Engineer
Team member
Callstack astronaut

Designer with Webflow

Sonia Głuszczuk
Designer with Webflow
Team member
Callstack astronaut

A 17-year-old React Native Developer with three years of experience. Started programming when he was 14 and currently doing mobile app development at Callstack, what makes him the youngest developer in the company! In his free time, Szymon likes to discover new and interesting technologies.

Szymon Rybczak
Software Engineer
Team member
Callstack astronaut

Project Manager with an experience in Web development who loves to make development easier for the whole team. As an ex-developer, he has great understanding of the client and developers needs. Personally, huge F1 fan and semi-professional simracing driver.

Sławomir Wiśniewski
IT Project Manager
Team member
Callstack astronaut

Loves using and building delightful applications, either web or mobile. Little big details matter (a lot). Spends his free time grinding coffee and buying LPs and JPEGs, not necessarily in this order. Currently situated somewhere between web2 and web3.Likes to build 3D experiences with Three.js, and his own models with Blender. Passionate about Daft Punk, and wants one of their helmets someday.

Thiago Brezinski
Software Engineer
Team member
Callstack astronaut

An experienced PM who gained skills working in banking corporations and software houses. Likes order - especially in the product design backlog. :-) Creating and optimizing processes, and building relationships through daily cooperation with interesting people of Callstack. What he values in managing projects is that you can always learn something new. He truly believes in the mighty power of Team Spirit. Conducting many different business and tech projects.

Tomasz Frąckowiak
IT Project Manager
Team member
Callstack astronaut

Pragmatic developer & code quality advocate. Interested in delivering uncompromised user experiences. Agile methodologies expert. He has a strong understanding of challenges regarding UX, accessibility, localisation, front-end security & code testing. Fun fact: he wrote his first program 30 years ago! ;) Loves chess & martial arts.

Tomasz Janiczek
Software Engineer
Team member
Callstack astronaut

IT Sourcer aka Sorcerer of Callstack 🔮, as part of the HR team, is mainly responsible for finding the best developers to our dream company. Constantly seeking for new ways/sources to recruit candidates. Privately, loves to play on the console, listen to R&B music from the 90's and getting into Japanese culture.

Tomasz Krupiński
Sourcing Team Lead
Team member
Callstack astronaut

React Native developer with strong background in web development. Experienced in projects for companies of all sizes, from start-ups to large corporations. Always doing his best to make the code clean and readable. On a day-to-day basis, focusing on React, React Native and Node.js. Loves all kind of sports, especially football and bike riding.

Tomasz Misiukiewicz
Software Engineer
Team member
Callstack astronaut

QA Tester, passionate about improving software, finding and fighting edge cases. She treats bugs like Pokémons — Gotta Catch 'Em All! Currently developing towards test automation, diving into programming and new tools. Unlike most, her energy drink is tea — she can drink up to 5 cups a day. Her main hobby is learning interesting facts about countries around the globe. She is also a happy dog owner, so she really likes to spend time outside.

Weronika Zyguła
QA Manual Engineer
Team member
Callstack astronaut

React Native Developer with a passion for exploring new technologies and learning new skills. Enthusiast of React ecosystem. Interested in performance optimizations, to provide a great experience and performant applications.

Wiktor Szlegier
Software Engineer
Team member
Callstack astronaut

React-Native developer who started his journey as a Front-end dev/graphic designer. Experienced in building mobile apps for both mobile and TV. Always eager to learn new things. Spends his free time dancing salsa and playing board games.

Wojciech Strzyż
Software Engineer
Team member
Callstack astronaut

Experienced React Native Developer with a background in Android development. Specialising in creating apps for multiple platforms: mobile, web and TV. Known for attention to detail and proactive approach. Constantly learning to stay ahead of industry trends and experiment with new ideas. Host of The React Native Show Podcast and Mentor in the field of Community and Trainings at Callstack.

Łukasz Chludziński
Expert Software Engineer
Team member
Callstack astronaut

Software developer with affection to React Native. Maintainer of the React Native Paper OSS library. Design systems enthusiast, who likes finding cross-platform solutions. Characterized by a precise and methodical approach to the problem. Open to exploring new technologies and development opportunities. Sport is an important part of his life.

Łukasz Walczak
Software Engineer
Team member
Callstack astronaut

Software developer with background in backend technologies, now happily focused on developing React Native apps. Always on the lookout for knowledge on new concepts and eager to adapt them in everyday work. Enjoys occasionally pulling all-nighters in hackathons and is interested in AR/VR field. Fan of outdoor activities, cycling and travelling.

Žilvinas Bartkus
Software Engineer

Mission

To drive and accelerate software development innovation. This informs our values:

Inclusion

We create equal opportunities. We aim at making the technology we co-create accessible to everyone everywhere. We provide an inclusive working environment.

Community

We value the Open Source community. We are happy to contribute to React and React Native ecosystems every day. We encourage knowledge sharing. We develop ideas within our R&D.

Challenge

We challenge existing solutions. We have the courage and curiosity to challenge the status quo, find innovative solutions and produce something unique. We work on apps used by millions and do projects for various clients.

Proactiveness

We constantly seek improvements. We bring passion and energy to work. We are always ready to discuss, challenge and submit ideas. We like to speak about everything React Native in our podcast.

Diversity

We respect uniqueness and individuality. Everyone is welcome to work with us, take part in our conference or other events. We embrace diversity to keep the workplace healthy and happy.

Excellence

We strive for perfection in everything we do. We are a team of experts whose goal is to achieve the highest standards. We have a self-development budget for every Callstacker.

Join us!

We are a great team of trusted React and React Native experts - passionate about what we do!
Callstack team