Senior NET Application Maintenance Engineer

Salary: up to 1300 PLN/MD on B2B Work model: hybrid from Gdynia | Warszawa | Kraków | Rzeszów Why choose this offer? Work in an agile and self-sufficient team with autonomy over development Collaborate with an English-speaking, multicultural team The client is one of the European leaders in its field and is building a completely new platform using the latest technologies The Jit community will bring you a nice time during regular integration meetings Enjoy work-life balance in a company that values flexibility and innovation Project We are looking for a highly skilled Senior .NET Application Maintenance Engineer to join our dynamic team. In this role, you will focus on maintaining, troubleshooting, and optimizing applications built with ASP.NET, .NET Core, and .NET Framework. Your expertise in MSSQL databases, debugging, and performance improvement will be crucial in ensuring smooth system operations. Our teams follow a T-shaped, cross-functional setup , meaning engineers contribute beyond their primary expertise. While you will focus on application maintenance, you should be comfortable taking on small tasks in different areas , including bug fixes, PR reviews, or DevOps contributions . We value collaboration and adaptability over rigid role definitions. What you'll be doing Maintain and support applications developed in ASP.NET, .NET Core, and .NET Framework Identify and resolve software and database performance issues Optimize SQL queries and stored procedures to improve system efficiency Collaborate with cross-functional teams to debug and resolve production issues Implement performance improvements and ensure application reliability Work with build and deployment tools (e.g., Jenkins, TeamCity, Azure DevOps) Communicate progress and technical updates to stakeholders and team members Expected competences and knowledge Bachelor's degree in Computer Science, Engineering, or a related field Strong development experience in .NET technologies (ASP.NET, .NET Core, .NET Framework) Expertise in troubleshooting production system issues Solid experience with MSSQL databases, SQL, and stored procedures A proactive, problem-solving mindset Previous experience in debugging and performance optimization Familiarity with CI/CD tools such as Jenkins, TeamCity, or Azure DevOps Strong communication skills to interact with both technical and non-technical stakeholders Technologies you'll work with .NET Framework, .NET Core, ASP.NET MSSQL CI/CD Tools Debugging & Performance Optimization Version Control DevOps Contributions Client – why choose this particular client from the Jit portfolio? Our client is a Scandinavian supplier of software and services for purchasing and tendering processes in highly formalized conditions, such as orders in accordance with public procurement law at the level of the European Union or individual member states. The delivery center is located in Utrecht. Client's platforms allow to announce tenders and conduct the entire procedure of collecting and evaluating offers at every stage of the purchasing process. They are used both by public administration bodies at various levels in European countries and by purchasing departments of large companies and corporations. 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 500 experienced experts . We create highly specialised teams for clients from all over the world. We offer team members developmental projects, a wide range of benefits and a proprietary professional development programme. Behind our maxim are also charitable and educational activities. We support pupils and students by donating learning equipment. We offer internships to help launch careers in IT. We support water rescuers and hospitals by providing the necessary equipment. We are a Polish company and we share what we have achieved over 15 years of activity . By supporting indigenous initiatives, we ensure the circulation of good energy.