Software Developer (.NET)

We are seeking an experienced Software Developer (.NET) to join an agile, cross-functional product team responsible for the design, development, and continuous evolution of a Gas Flow Management (GFM) digital platform. The solutions developed by the team support end-to-end commercial and operational processes in large-scale energy infrastructure environments. These systems span the full gas flow lifecycle, including customer onboarding, contracting, demand handling, flow planning, network balancing, billing and invoicing, data publication, reporting, and business-to-business messaging. This role offers the opportunity to work on a long-lived, mission-critical product, where software quality, architectural integrity, and business alignment are essential. You will actively contribute to feature design, system evolution, and technical decision-making in a context of high reliability and regulatory complexity. Key Responsibilities Design, develop, and maintain high-quality, scalable, and maintainable .NET-based software components Translate complex business and operational requirements into robust technical solutions in close collaboration with product owners and analysts Contribute to architectural discussions, proposing improvements that enhance performance, reliability, and long-term maintainability Implement automated tests and actively participate in functional and technical testing activities Perform code reviews, share knowledge, and uphold agreed development standards Support release preparation, including technical documentation and deployment activities Participate in user acceptance testing (UAT) and product demonstrations, ensuring solutions are understandable and usable for business stakeholders Handle functional and technical service requests, providing timely and effective support Investigate and resolve incidents collaboratively, minimising operational impact Monitor and troubleshoot issues across development, testing, and production environments Actively participate in Agile ceremonies, including backlog refinement, sprint planning, reviews, retrospectives, and daily stand-ups Contribute to the product backlog by creating technical items expressed in business-oriented language, supporting value-based prioritisation Technical Skills Core Technologies Backend: .NET 8 / .NET Framework, ASP.NET Web API, WCF Data & Messaging: SQL Server, Oracle, RabbitMQ, NHibernate, Entity Framework Architecture: Domain-Driven Design (DDD), Clean Architecture, design patterns Testing & CI/CD: xUnit / NUnit, Azure DevOps Pipelines Frontend: Blazor (nice to have) DevOps & Tooling: Git, Azure DevOps, automated deployment and monitoring tools Professional Competencies Strong foundation in software design principles and clean coding practices Experience working with complex, enterprise-grade systems and long-term codebases Solid understanding of testing strategies and CI/CD pipelines Ability to communicate effectively with both technical and non-technical stakeholders Fluency in Portuguese and English (C1 level) ; knowledge of French or Dutch is an advantage Mindset & Ways of Working Product-oriented: You focus on delivering tangible value, not just completing tasks Collaborative: You work effectively within multidisciplinary teams and value shared ownership Analytical and Curious: You challenge assumptions and seek continuous improvement Adaptable: You remain effective in changing environments and evolving priorities Quality-driven: You prioritise sustainable, reliable solutions over short-term fixes Accountable and Transparent: You take ownership of outcomes and communicate openly Committed to Learning: You stay engaged with evolving technologies, domains, and practices Practical Information Location: Lisbon Working Model: Hybrid – on-site presence required two days per week