Job offer

JavaScript Developer


Callstack supports and inspires other developers and companies to launch their products for everyone, at the same time, on every platform. We are strong open source contributors, core contributors to React Native, cross-platform development experts and a team of developers passionate about new technologies. We pride ourselves on providing sustainable, top-end solutions to our clients from all around the world. We are recognized in React Native Community as contributors to Open Source projects, organizers of React Native EU as well as speakers at several international conferences. We also organize regular community meetups in our HQ in Wrocław, Poland.

We are looking for a skillful JavaScript Developer with React knowledge to join our team of cross-platform development experts. In this role you will act as a technology consultant and guide our clients through the most complex challenges of cross-platform development. You will also have a chance to contribute to the open source community by working on challenging projects, speaking at conferences and sharing your knowledge with the world.


You will

  • Act as a technology consultant and help our clients build great products for multiple platforms.
  • Drive the development process by providing expertise on cross-platform technologies and tackling most complex programming issues.
  • Collaborate with development teams, CTOs, Project Managers and Product Owners from all around the world.
  • Have multiple possibilities to contribute to the open source community by working on projects led by our CTO, React Native core contributors and our Senior Developers.
  • Conduct workshops, speak at conferences and meetups, write blog posts and articles.


What we look for

  • A proficient JavaScript developer who presents extensive knowledge and expertise within modern frameworks, libraries and best practices, with emphasis on React.js.
  • Experience in building complex async applications (e.g. with help of Redux, Sagas, Observables).
  • Ability and willingness to quickly acquire new technical expertise.
  • Strong drive towards learning new technologies and knowledge-sharing initiatives.
  • Engagement in open source or willingness to start contributions right away.
  • Proactive problem solving approach.
  • Great command of English (minimum B2).

Bonus points

Nice to have

  • React Native knowledge.
  • Experience with mobile apps development (iOS and/or Android).
  • Familiarity with other cross-platform technologies like Flowtype, Jest, ReasonML, Flutter or PWA.
  • Knowledge of software architecture and readiness to act as a Software Architect when required.
  • Knowledge of Node.js or other backend capabilities.
  • Familiarity with algorithms and performance topics.
  • Prior experience with speaking at conferences and meetups or a willingness to start doing so.
What we offer
  • Working side by side with core contributors of several open source projects such as React Native and Jest.
  • Free entry for React Native EU conference. We will also support your participation in other international tech conferences and workshops.
  • Private healthcare for you and your family - we do care about your health and wellbeing.
  • Co-financed Multisport Card or monthly allowance for other gym and sports activities - you choose!
  • Free lunches delivered to our office every day! Or a monthly lunch allowance if you prefer eating outside.
  • Fresh fruits, snack & sodas in our kitchen.
  • Fully-covered life insurance.
  • 24 paid days off and paid sick leave for B2B contractors.
  • Accounting costs refund for B2B contractors.
  • Flexible working hours and remote work possibilities.
  • Individual self-development budget.
  • Top-notch hardware - MacBook Pro, monitor and peripheral devices.
  • Recurring team events - workation, weekend ski rides, cooking workshops, board games nights and parties.
  • Cool office in the city center.

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