Senior Backend Developer (Kotlin/Spring Boot)
This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Senior Backend Developer (Kotlin/Spring Boot) based in Ireland.
This role is part of a highly technical healthtech initiative focused on rebuilding a core FHIR server from the ground up. You will be working on complex, abstraction-heavy backend engineering challenges, going far beyond standard API development. The primary focus is the design and implementation of a dynamic query engine capable of interpreting flexible parameters and FHIR structure definitions at runtime. You will join an existing team of engineers and contribute to a shared architecture, working collaboratively on design decisions and system evolution. The environment is deeply technical, with strong emphasis on scalability, correctness, and healthcare interoperability standards. This is a hands-on role where your work will directly influence the backbone of modern healthcare data infrastructure.
Accountabilities:
- Design and implement high-abstraction backend components, with a focus on a dynamic query engine for FHIR-based data structures
- Contribute to the development of a custom FHIR server built in Kotlin and Spring Boot
- Collaborate with a small engineering team to define architecture, split tasks, and align on technical direction
- Develop and maintain robust backend services using PostgreSQL, including JSONB-based data modeling and complex queries
- Build and expand comprehensive automated test coverage using JUnit to ensure system reliability
- Integrate and work with healthcare data standards such as FHIR R4 where applicable
- Participate in technical discussions, surfacing blockers and refining system design with the team
- Support secure authentication and authorization patterns using OAuth and identity management systems
- Ensure backend systems are scalable, maintainable, and aligned with long-term platform goals
Requirements:
- Strong experience in backend development using Kotlin and/or JVM-based technologies
- Solid hands-on experience with Spring Boot in production environments
- Proven ability to build or contribute to high-abstraction systems such as query engines, rule engines, or dynamic processing frameworks
- Strong knowledge of PostgreSQL, including advanced querying and JSONB data modeling
- Experience writing and maintaining comprehensive automated test suites using JUnit
- Ability to work collaboratively within a small engineering team and align on shared architectural decisions
- Strong communication skills with fluent English (minimum B2 level) for daily technical collaboration
- Comfortable working remotely within Europe and engaging in distributed team workflows
- Bonus: familiarity with HL7 FHIR (R4), HAPI FHIR, or healthcare data systems
- Bonus: experience with OAuth flows, identity providers such as Zitadel, or authorization systems like SpiceDB
Benefits:
- Competitive compensation aligned with senior-level expertise
- Fully remote work within Europe with flexible collaboration
- Opportunity to work on a cutting-edge healthcare infrastructure project
- Exposure to complex, real-world FHIR and healthcare interoperability challenges
- Close collaboration with experienced engineers in a highly technical environment
- Strong influence on architecture and system design decisions
- Long-term engineering impact on a critical healthcare data platform
- International, collaborative, and engineering-driven culture
