Build once, deploy everywhere: multiplatform FHIR development on Android, iOS, and Web
byThe mission of Google's Open Health Stack team is to accelerate digital health innovation by providing developers everywhere with critical building blocks for next-generation healthcare applications. Expanding its existing components, the team has released Kotlin FHIR (currently in alpha), a new open-source library now available on GitHub. It implements the HL7® FHIR® data model on Kotlin Multiplatform (KMP), enabling developers to build FHIR apps and tools for Android, iOS, and Web simultaneously.
Tools to support health data exchange using a modern standard
HL7® FHIR® (Fast Healthcare Interoperability Resources) is a global interoperability standard for healthcare data exchange. It enables healthcare systems to exchange data freely and securely, improving efficiency and transparency while reducing integration costs. Over the years, it has seen rapidly growing adoption, and its use has been mandated by health regulations in an increasing number of countries.
Since March 2023, the Open Health Stack team at Google has introduced a number of tools to support FHIR development. For example, the Android FHIR SDK helps developers to build offline capable FHIR-native apps that can help community health workers carry out data collection tasks in remote communities. With FHIR Data Pipes, developers can build analytics solutions more easily to generate critical insights for large healthcare programmes more easily. Today, apps powered by these tools are used by health workers covering over 75 million people across Sub-Saharan Africa, South and Southeast Asia.
A leap forward to multiplatform development
In low-resource settings, it is imperative to develop apps that can reach as many patients as possible at a low development cost. However, a lack of infrastructure and tooling often hinders this goal. For example, Kotlin Multiplatform (KMP) is a new and exciting technology rapidly gaining traction, but existing FHIR libraries are not suitable for KMP development due to their platform-specific dependencies. Consequently, developing FHIR apps on KMP has not been possible, causing developers to miss out on a significant opportunity to scale their solutions.
Introducing Kotlin FHIR. It is a modern and lightweight implementation of FHIR data models designed for use on KMP with no platform-specific dependencies. With Kotlin FHIR, developers can build FHIR apps once, and deploy them to Android, iOS, Web, and other platforms.
"Any library that helps implementers use FHIR is my favourite, but I'm particularly thrilled to see a new library from the awesome Open Health Stack team.
– Grahame Grieve, Creator of FHIR, Product Director at HL7
Modern, lightweight, and sustainable
Kotlin FHIR uses KotlinPoet to generate the FHIR data model directly from the specification. This ensures that the library is complete and maintainable. The data model classes it generates are minimalist to provide the best usability for developers: it has everything that you need, nothing less and nothing more. It uses modern language features in Kotlin such as sealed interfaces to ensure type-safety and to give developers the best coding experience. It supports all the FHIR versions: R4, R4B and R5, and will be updated when new FHIR versions are released.
The library is currently in alpha, but has received positive feedback from the developer community. To try FHIR multiplatform development using the library, head to the repository.
Beyond data models: more on multiplatform
Our mission is to empower the digital health community, and the Kotlin FHIR library is our latest step in that effort. But handling the FHIR data model on KMP is just the beginning. Rich features provided by the Android FHIR SDK libraries will also be needed on KMP. This is a collaborative effort, and we invite the FHIR community to join us in defining and building the cross-platform tools you need most. To learn more about how you can get involved, head to the Open Health Stack developer site.
