FHIR Backend Developer | .NET

You'll contribute to the development and improvement of Firely Server, our flagship FHIR server product. That means building new features, improving performance, and helping shape the technical direction of what we ship.

In this role, you will:

• Design and implement backend features in .NET / C#
• Work with REST APIs to enable reliable health data exchange
• Write and optimize queries across MS SQL Server and/or MongoDB; including indexing strategies and schema design for healthcare data
• Handle and validate JSON/XML payloads in line with FHIR specifications
• Contribute to code reviews, technical discussions, and architectural decisions
• Use AI tools to support development, planning, and quality assurance
• Collaborate with colleagues and, where relevant, engage with the wider FHIR community

Do you have experience in XML?, Do you have a Bachelor's degree?, You're someone who takes ownership, asks good questions, and cares about the quality of what you ship. You're energized by technically challenging work, comfortable with ambiguity, and not put off by a spirited debate in the FHIR community.

Required

• Proficiency in .NET / C# backend development
• Solid understanding of REST APIs and how to work with them effectively
• Database experience with MS SQL Server and/or MongoDB
• Experience withAWSor Azure
• Experience handling JSON/XML payloads, including validation and storage
• Experience using AI tools to support development, planning, and quality assurance
• Familiarity with Git and tools like Jira, GitHub Projects
• Already authorized to work in the Netherlands
• Fluent English (written and spoken)

Nice to have

• A bachelor's degree in computer science or equivalent working level
• At least 2 years of .NET / C# backend development experience
• Knowledge of HL7 and/or FHIR
• Familiarity with additional data stores such as PostgreSQL or cloud-native databases (e.g.Azure Cosmos DB, AWS RDS)
• A background in or curiosity about the healthcare sector

We want this to be a place where you can do great work, keep growing, and feel genuinely trusted with things that matter. You can expect:

• Real ownership of your work, with support from experienced colleagues
• Plenty of room to develop your skills across a technically rich stack
• Active involvement in hackathons and international FHIR working group meetings
• A salary between €5,000 and €6,000 gross per month based on a 40-hour workweek
• 27 holidays based on a 40-hour work week
• A hybrid role (with 2 days in the office), full-time or 4 days - you choose
• NS Business Card to travel 1st class to work
• Bring your own device or budget to purchase a new one
• Budget to set-up your home office
• Annual budget to support your growth and development
• A cozy office in the heart of Amsterdam with a canal view Questions about this role? Reach out to our HR & Recruitment team at recruitment@fire.ly

At Firely, we build enterprise-grade software that makes health data more accessible and more useful. Our FHIR server is at the heart of that work, helping healthcare organizations around the world exchange data more reliably and efficiently. Yes, it's technical. But it's also meaningful. Better health data exchange means better informed care. To help us push that further, we're looking for a talented and curious Backend Developer (.NET) to join our development team. This role is for someone who enjoys owning their work, diving into hard problems, and contributing to a standard that's shaping the future of healthcare. You'll work in a small, collaborative team alongside a product owner, lead developer/architect, and fellow engineers. You'll have real autonomy over your technical scope and senior colleagues to think alongside when the problems get complex.