.NET Fullstack Engineer (f/m/d)

.NET Fullstack Engineer (f/m/d) Energy trading moves fast, and the tools behind it need to keep up. You'll become the go-to person for a complex, business-critical application at the heart of Axpo's energy trading operations. You'll start by working alongside external developers to deeply understand the system and its business logic, then progressively take ownership — delivering change requests, supporting users and driving technical improvements. Over time, you'll modernize legacy logic into clean .NET code, improve test coverage and help evolve the frontend. This is hands-on, technical work on a real system with real users. Tasks and Responsibilities : Learn, document and internalize application logic and business rules currently held by external developers. Deliver change requests, bug fixes and small features to continuously add business value. Provide L1/L2 support: assess and prioritize reported issues, diagnose root causes, implement fixes or workarounds. Design and develop ASP.NET Core APIs and background services. Maintain and evolve the frontend (Angular). Ensure quality through automated testing and solid CI/CD practices. Collaborate with analysts, architects and engineers to plan and deliver iteratively. Use AI-assisted tools (LLMs, Copilot) to accelerate development and refactoring. Contribute to technical documentation and architectural decisions. Over time, rearchitect and modernize application components, bringing business logic into clean, testable .NET code. Qualifications : Education : University degree in Software Engineering or a quantitative subject. Professional Competencies : Must-have: 5+ years of experience with C#/.NET (ASP.NET Core, RESTful APIs); strong OOP and clean code practices. Solid SQL skills — comfortable working with complex queries, stored procedures and database logic. Experience with Angular (v17+). Experience with automated testing and CI/CD pipelines (Azure DevOps or GitHub Actions). Effective use of AI coding assistants to boost productivity. Nice-to-have : Familiarity with ORM tools (e.g. Entity Framework Core) and data access patterns. Experience with other modern frontend frameworks (e.g. React) Messaging systems (RabbitMQ, Azure Service Bus, Kafka). Cloud & DevOps (Azure, Terraform, Ansible). Real-time frameworks (SignalR). Observability tools (Elastic Cloud, Application Insights). Experience with application modernization projects. Familiarity with the energy sector. Personal Competencies : Analytical problem-solver who thrives on complexity. Clear communicator and collaborative team player. Curious learner who embraces new tools and ways of working. Languages : Proficient in English. Benefits: At our company, we strive to create a culture of continuous learning, personal growth, and inter- national community involvement. We're passionate about providing our employees with the tools and resources they need to succeed, and we're confident that you'll love being part of our team! Working Hours We offer flexible working hours to accommodate your work schedule. 60% on remote and 40% at our offices in Madrid, Torre Europa. Meal allowances You can enjoy delicious meals on us, no matter if you are working remotely or on-site. *Option to use it for public transportation or childcare instead. Internet Compensation We cover the cost of your home internet connection, as we understand how essential connectivity is in the modern workplace. Training courses Our company is committed to helping our employees grow and develop their skills, which is why we offer a variety of industry- specific training courses and a learning channel. Gym Coverage Stay active and healthy with our 90% coverage benefit, which provides access to the nearby gym: Forus Selection to keep you energized throughout the day Health Insurance We take the health and well-being of our employees seriously, which is why we offer a comprehensive health insurance plan and the option to extend it to your spouse and children. At Axpo Group, we are dedicated to fostering a culture of non-discrimination, tolerance, and inclusion. As an equal opportunity employer, we welcome applications regardless of race and ethnicity, gender identity and expression, sexual orientation, age, disability, as well as socioeconomic, cultural, and religious background. We are committed to ensuring a respectful and inclusive recruiting process and workplace for everyone. Department IT / Technology Locations Madrid Remote status Hybrid Faces of Axpo More videos About Axpo Group Axpo's ambition is to provide society with a sustainable future through innovative energy solutions. Axpo is the largest Swiss producer of renewable energy and an international pioneer in energy trading and the marketing of solar and wind power. More than 7,500 employees combine experience and know-how with a passion for innovation and the joint search for ever better solutions. Axpo relies on innovative technologies to meet the ever-changing needs of its customers in over 30 countries in Europe, North America and Asia. Founded in 1908 Co-workers 7500