Unleash innovation — build next-generation software solutions that transform industries!Warsaw-based opportunity with hybrid work model (2 days in the office/month).As a Senior Fullstack .NET Developer you will be working for our client, a major digital financial services organization delivering secure, high-availability online banking platforms at scale. You will contribute to the design and evolution of mission-critical systems used by millions of users, supporting complex transactional workflows and regulatory requirements. The role focuses on building and maintaining microservice-based solutions, modern web front ends, and cloud-ready infrastructure, while collaborating closely with cross-functional teams to continuously improve performance, reliability, and developer experience across the platform.Your main responsibilities: Design and develop backend services using C# and .NET technologies Build and maintain modern frontend applications with Angular and JavaScript Implement REST APIs supporting scalable and secure integrations Apply SOLID principles, design patterns, and dependency injection Develop and maintain automated unit and E2E tests Design and implement microservice-based architectures Optimize data access using relational databases Integrate messaging and caching solutions within distributed systems Collaborate with DevOps teams to support CI and CD pipelines Deploy and operate services using containerization and orchestration tools You're ideal for this role if you have: Minimum 5 years of experience with C#, .NET Core, and .NET Framework Senior-level expertise in Angular and JavaScript Strong knowledge of SOLID principles, design patterns, IoC, and DI Extensive experience with unit and E2E automated testing Senior-level experience designing and consuming REST APIs Proven experience with microservice architectures Hands-on experience with Docker and Kubernetes Working knowledge of MSSQL and PostgreSQL Experience with CI and CD processes and tools Familiarity with messaging, caching, and observability tools such as Redis, RabbitMQ, or Grafana Experience with Ansible or readiness to learn it ​​​​​​​Nice to have: Experience in deploying systems on cloud platforms, such as Azure or GCP #MAKEYourCareerBETTERInterested? Apply now and include your CV in English or Polish, along with a statement confirming your consent to the processing and storage of your personal data.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 various industries. 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.  You can report violations in accordance with ITDS’s Whistleblower Procedure available here.  Ref. number  8258