Senior .NET Developer NEW

Jit; Warszawa; Hybrid; PLN 180,000 - 240,000; Full time

Job summary

Jit Team is seeking a backend developer to design, build, and maintain .NET/C# applications, focusing on microservices, distributed systems, and REST APIs for a leading Polish e‑commerce platform. The role emphasizes high availability, performance, and collaboration with product teams and architects.

You will participate in code reviews and mentorship, contributing to architectural decisions and ongoing system improvements while enjoying a fully remote setup with occasional visits to Warsaw or

Qualifications

• Minimum 4 years of professional experience with .NET / C#
• Strong experience in backend development and API design
• Practical experience with microservices and distributed systems
• Good knowledge of SQL and relational databases
• Practical experience with Microsoft Azure
• Very good knowledge of Git
• Understanding of software architecture and design patterns
• Experience with performance analysis and optimization
• Experience with code reviews and preferably mentoring
• Ability to collaborate effectively with product teams, architects, and other technology teams
• English at B2+ level

Responsibilities

• Designing, developing, and maintaining backend applications using .NET / C#
• Developing and maintaining microservices and distributed systems
• Designing and implementing REST APIs for business applications and services
• Participating in software architecture and technical design decisions
• Collaborating with product teams, architects, and other technology teams
• Performing code reviews and ensuring high code quality
• Analyzing and optimizing application performance
• Maintaining and optimizing high-availability systems
• Supporting technical improvements and continuous development of existing solutions
• Sharing knowledge and providing technical mentoring to other team members

Job description

Work model: Full remote, with occasional office visits in Warsaw or Kraków

Why choose this offer?

• Impact on the development of thelargest e-commerce systemin Poland
• You can expect aflexible work organization
• Long-term cooperation within a stable ecosystem
• TheJit communitywill bring you a nice time during regular integration meetings

Project

Development and maintenance of backend applications based on .NET, including the design and development of microservices and distributed systems. The project involves building and integrating APIs supporting business applications and services, optimizing high-availability solutions, and contributing to architectural decisions and technical design. Close collaboration with product teams, architects, and technology teams, with a strong focus on code quality, performance, and continuous improvement.

Responsibilities

• Designing, developing, and maintaining backend applications using .NET / C#
• Developing and maintaining microservices and distributed systems
• Designing and implementing REST APIs for business applications and services
• Participating in software architecture and technical design decisions
• Collaborating with product teams, architects, and other technology teams
• Performing code reviews and ensuring high code quality
• Analyzing and optimizing application performance
• Maintaining and optimizing high-availability systems
• Supporting technical improvements and continuous development of existing solutions
• Sharing knowledge and providing technical mentoring to other team members

Expected competences and knowledge

• Minimum 4 years of professional experience with .NET / C#
• Strong experience in backend development and API design
• Practical experience with microservices and distributed systems
• Good knowledge of SQL and relational databases
• Practical experience with Microsoft Azure
• Very good knowledge of Git
• Understanding of software architecture and design patterns
• Experience with performance analysis and optimization
• Experience with code reviews and preferably mentoring
• Ability to collaborate effectively with product teams, architects, and other technology teams
• English at B2+ level

Nice to have

• Docker
• Event Sourcing
• PowerShell/Bash

Technologies you'll work with

• REST APIs
• Microservices & distributed systems
• SQL / SQL Server
• Git
• Docker
• Event Sourcing
• PowerShell / Bash

Client – why choose this particular client from the Jit portfolio?

Our Client dominates the Polish e-commerce arena as the market leader since 1999. With a user base of over 20 million and growing, this well‑established platform is at the forefront of e‑commerce, constantly striving for growth through market expansion and investment. As a major player in technology, our Client boasts a talented IT team of over 1,000 employees who focus on developing their own cutting‑edge technologies.

Jit Team has had a successful partnership with our Client since spring 2021, with multiple software development teams dedicated to our Client's platforms. These teams operate autonomously, designing platform components through micro‑services.

Working with our Client offers a chance to contribute to a solution used by millions on a daily basis and to tackle the challenge of delivering software at a massive scale, where even a single second of delay can have a significant impact. This project provides a unique opportunity to work with state‑of-the‑art technologies and tools, making it a rare and valuable experience.

About Jit Team

The Human Factor of IT - it’s not just a slogan, it’s a philosophy. The foundation of Jit Team is people, which is why we prioritise you. We employ over 770 experienced experts , to whom we offer developmental projects, a wide range of benefits, and a proprietary professional development programme. Together with clients from around the world, we create innovative IT solutions delivered by highly specialised and efficient teams.

Behind our maxim are also charitable and educational activities. We support schools, universities, and educational institutions by conducting workshops, running educational projects, sponsoring events, and donating learning equipment. We offer internships that help launch careers in IT. We support water rescuers and hospitals by providing the necessary equipment. We also support numerous charitable organisations helping people in need, children, and the elderly. We are a Polish company and we share what we have achieved over more than 15 years of activity. By supporting local initiatives, we contribute to the circulation of good energy.