Senior Backend .NET Developer

Job description

Twoday is the leading digital transformation partner in Northern Europe with a global presence. With approximately 3,000 specialists, we collaborate with some of the most admired private and public organisations to deliver cutting-edge digital solutions. Our expertise spans software engineering, Data & AI, cloud platforms, digital experiences and business applications. We are now looking for a Senior Platform Engineer to help transform a large-scale development and deployment platform from traditional DevOps into a modern AI-assisted and agentic engineering setup. Permanent position at Twoday | Copenhagen Senior Backend .NET Developer – Digital Health Digital Engineering | Copenhagen Senior Backend .NET Developer – Digital Health Do you want to build and evolve business-critical digital solutions that support Denmark’s healthcare sector? Twoday is looking for experienced Backend .NET Developers to join a major, long-term digital health delivery in Copenhagen. You will work with complex systems where reliability, security, maintainability and technical quality are essential – and where the solutions you help build and operate have a direct impact on critical public services. This is a permanent position with Twoday, where this delivery would, if we win the tender, become your first assignment as a consultant with us. The role The customer is introducing a new delivery model in which several suppliers will collaborate closely on the development, maintenance and operation of a portfolio of business-critical healthcare applications. Rather than operating as separate supplier organisations, developers from different companies will work together in shared teams. This makes technical expertise essential, but it also requires engineers who collaborate well, share knowledge and take responsibility for the overall delivery – not just their own code. As a Senior Backend .NET Developer, you will work hands-on throughout the software delivery lifecycle: from analysis and refinement through design and development to testing, deployment, maintenance and troubleshooting in production. You will be expected to contribute to building robust solutions and to take technical ownership in close collaboration with other developers, Solution Architects, testers, DevOps specialists and product stakeholders. Your responsibilities will include: Designing, developing and maintaining backend services and server-side components Developing APIs and integrations across a complex application landscape Contributing to application design, data modelling and technical decision-making Working with microservices, distributed systems and event-driven architectures Designing for resilience, scalability, high availability and operational stability Working with messaging technologies and asynchronous communication Building and maintaining automated build, test and deployment pipelines Contributing to containerised deployment and modern infrastructure practices Implementing appropriate logging, monitoring and observability Applying secure coding practices and considering security and privacy throughout the development lifecycle Writing automated tests and contributing to high standards for code quality and documentation Diagnosing and resolving issues across release and production environments Contributing to backlog refinement and translating requirements into technically sound solutions Sharing knowledge and collaborating across teams and suppliers The formal role includes both development and operation of server-side components as well as version control and automated pipelines. What we are looking for You are an experienced, hands-on backend engineer with a strong foundation in C# and .NET and a track record of developing complex, business-critical software. You are comfortable looking beyond an individual feature or service and understand how architecture, integration, data, security, deployment and operations come together in a production environment. We are particularly interested in experience with several of the following: C# and modern .NET / .NET Core Core and backend service development REST APIs and systems integration Microservices and distributed systems Messaging and event-driven architectures, such as Kafka or comparable technologies SQL, data modelling and transactional systems Domain-driven design and modern software architecture principles Docker, containers and modern deployment practices CI/CD and automated delivery pipelines Azure DevOps or comparable engineering platforms Git and collaborative development workflows Automated testing and quality engineering Observability, monitoring and production troubleshooting Authentication, authorisation and secure software development Resilience patterns and highly available systems Agile software development Experience from healthcare, Danish public-sector IT or other complex and regulated environments is a strong advantage. Healthcare knowledge is not a prerequisite for every position on the team, but relevant experience from the healthcare domain will be particularly valuable. Who you are You are still close to the technology and enjoy solving difficult engineering problems. You take ownership of your work from understanding the problem to seeing the solution perform reliably in production. At the same time, you recognise that seniority is not only about technical depth. You contribute constructively to technical discussions, challenge solutions when needed, support colleagues and help the team make sound engineering decisions. The delivery will involve close collaboration across organisational boundaries, so you should be comfortable working transparently with colleagues from different companies and contributing to a shared engineering culture. You must be fluent in spoken and written Danish and English. The role is based in Copenhagen and requires a significant degree of onsite work at the customer. Join Twoday At Twoday, you will join a strong professional technology environment with colleagues working across software engineering, architecture, cloud, data and digital transformation. This is a permanent position with Twoday, where this delivery would, if we win the tender, become your first assignment as a consultant with us. Your employment is with Twoday and is not limited to this particular customer or project. For the right developer, this is an opportunity to combine deep backend engineering with a long-term assignment in an important and technically complex area of Danish digital infrastructure. We look forward to hearing from you. About Twoday Twoday operates from modern offices across 30 locations in Norway, Sweden, Denmark, Finland, and Lithuania. We have a strong and unique social environment with highly engaged employees. If you are the candidate we are looking for, you will play a central role with exciting opportunities to grow within an international and innovative group, working on cutting-edge technology and software solutions. You will also have the flexibility to occasionally work from one of our main offices in Oslo, Stockholm, Copenhagen, Helsinki or Vilnius. Diversity & inclusion Do you not meet all the requirements? Studies show that women and minorities are less likely to apply for a job if they don’t meet every qualification. At Twoday, we are committed to building a workplace and community where everyone is welcome. If you are excited about this role but your previous experience doesn’t perfectly align with the job description, we still encourage you to apply.