[Updated February 2026]
These are all the Open Source FHIR servers I am aware of. Most are R4 servers though some have R5 versions. The HAPI server is the most commonly used for production level applications but don’t discount the others as each have their own strengths.
All come with permissive licenses and all apart from the IBM server are under active development.
Here they are, in no particular order:
1. HAPI
https://github.com/hapifhir/hapi-fhir
Language: Java
Status: Under active development
License: Apache 2.0
2. Microsoft
https://github.com/microsoft/fhir-server
Language: C#
Status: Under active development
License: MIT
3. Incindi
https://github.com/FirelyTeam/spark
Language: C#
Status: Under active development
License: BSD-3
4. Blaze
https://github.com/samply/blaze
Language: Clojure
Status: Under active development
License: Apache 2.0
5. Medplum
https://github.com/medplum/medplum
Language: TypeScript
Status: Under active development
License: Apache 2.0
6. Ballerina
https://github.com/ballerina-platform/module-ballerinax-health.fhir.r4
Language: Ballerina
Status: Under active development
License: Apache 2.0
7. Bwell
https://github.com/icanbwell/fhir-server
Language: JavaScript
Status: Under active development
License: MIT
8. DirectFHIR
https://github.com/metacareforyou/directfhir
Language: JavaScript
Status: Under active development
License: Apache 2.0
9. IBM
https://github.com/LinuxForHealth/FHIR
Language: Java
Status: Not under active development
License: Apache 2.0
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