Innovate online banking and join the team as a Senior .NET Developer!Warsaw/Łódź-based opportunity with hybrid work model (2 times in the office/month).As a Senior .NET Developer you will be working for our client, a leading company in the online banking sector that is currently expanding its digital solutions to provide secure, scalable, and efficient services to millions of customers. You will play a key role in developing and implementing backend systems that ensure high performance and reliability, while also taking responsibility for guiding project design, development, and deployment. This position offers the opportunity to contribute to cutting-edge financial solutions while collaborating with a highly skilled technical team.Your main responsibilities: Implement backend solutions using .NET Core, .NET Framework, and MS SQL Ensure high code quality by writing unit and automated tests Lead project design, development, and deployment activities Collaborate with cross-functional teams to define technical requirements Review and optimize code to improve performance and scalability Maintain technical documentation and contribute to knowledge sharing Support integration of REST APIs with internal and external systems Mentor junior developers and provide technical leadership You're ideal for this role if you have: At least five years of experience in backend development with C#, SQL, and REST API Advanced knowledge of .NET Framework, .NET Core, and ASP.NET WebAPI Strong understanding of architectural patterns for scalable and high-performance solutions Proficiency with version control and collaboration tools such as Git, Jira, and Confluence Experience in writing unit and automated tests Ability to design and implement secure, reliable, and maintainable solutions Strong problem-solving and analytical skills Solid communication skills in English for reading, writing, and technical discussions Ability to work independently as well as in a team-oriented environment Nice to have: Knowledge of:

masstransit nservicebus, Elasticsearch Kubernetes 

We offer you:ITDS Business Consultants is involved in many various, innovative and professional IT projects for international companies in the financial industry in Europe. We offer an environment for professional, ambitious, and driven people. The offer includes:  Stable and long-term cooperation with very good conditions  Enhance your skills and develop your expertise in the financial industry Work on the most strategic projects available in the market Define your career roadmap and develop yourself in the best and fastest possible way by delivering strategic projects for different clients of ITDS over several years Participate in Social Events, training, and work in an international environment Access to attractive Medical Package Access to Multisport Program Access to Pluralsight Flexible hours & remote work