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December 17, 2025

React Developer with .NET

Mid • Remote

Białystok, Poland

Sii ensures that all employment-related decisions are made solely on the basis of qualifications and competencies. We are committed to equal treatment of all individuals, regardless of any protected characteristics, and promoting a diverse and inclusive work environment.

We are looking for a React Developer with solid .NET/C# knowledge to join our team for a project in the automotive industry. You will work on building and improving high-quality applications used in a dynamic and fast-growing environment.

Your tasks

Develop and maintain advanced frontend applications using React
Implement backend functionalities and APIs using .NET/.NET Core
Collaborate closely with product owners, designers, and QA teams to deliver high-quality features
Optimize application performance and ensure best UI/UX practices
Participate in code reviews, architectural discussions, and continuous improvement initiatives

Requirements

Minimum 3 years of professional experience as a Frontend or Fullstack Developer
Strong expertise in frontend technologies, including React, TypeScript, and JavaScript
Solid working knowledge of .NET / .NET Core for backend development
Strong communication skills and the ability to collaborate in cross-functional teams
Communicative English proficiency, both spoken and written
Residing in Poland required

What we offer

Great Place to Work since 2015 - it’s thanks to feedback from our workers that we get this special title and constantly implement new ideas
Employment stability - revenue of PLN 2.1BN, no debts, since 2006 on the market
We share the profit with Workers - over PLN 76M has already been allocated for this aim since 2022
Attractive benefits package - private healthcare, benefits cafeteria platform, car discounts and more
Comfortable workplace – class A offices or remote work
Dozens of fascinating projects for prestigious brands from all over the world
PLN 1 000 000 per year for your ideas - with this amount, we support the passions and voluntary actions of our workers
Investment in your growth – meetups, webinars, training platform and technology blog – you choose
Fantastic atmosphere created by all Sii Power People

If you're ready to take on a new challenge and grow your skills, this role is a great opportunity. Apply and join our team!

Sii

Sii is a company recognized as a "Great Place to Work" since 2015, thanks to employee feedback and the implementation of new ideas. Established in 2006, Sii has demonstrated financial stability with a revenue of 2.1 billion PLN and no debts. The company shares its profits with employees, having allocated over 76 million PLN for this purpose since 2022. Sii offers a rich benefits package, including private healthcare, a cafeteria platform, and discounts on cars. Employees can work in comfortable A-class offices or remotely. Sii is involved in numerous fascinating projects for prestigious global brands and invests 1 million PLN annually to support employee passions and volunteer actions. The company emphasizes personal development through meetups, webinars, a training platform, and a technology blog. Sii is characterized by a fantastic atmosphere created by its "Sii Power People."

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