.NET Fullstack Engineer

Axpo

Madrid, Spain

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.