Narrative in
Clinical notes arrive as free text, with the abbreviations and variation found in real care.
Deterministic Narrative to FHIR using LLMs
FHIR at Will is the bridge.
An open-source, AI-powered interoperability layer that turns your Unstructured narrative clinical data into FHIR R4 resources—while your infrastructure evolves.
</> open source
⎈ self-hostable
↯ byok / byom
☷ implementation-guide aware
FHIR at Will implements an 8-layer validation cascade so you can trust what you interoperate.
› Verification-first by design
L1StructuralIs it valid FHIR R4?
L2ProfileDoes it conform to required profiles?
L3TerminologyAre codes valid and in their ValueSets?
L4InvariantsDo FHIRPath invariants hold?
L5PlausibilityIs the value clinically possible?
L6FidelityIs each element supported by source data?
L7CoverageWhat clinical information was omitted?
L8RoutingAuto-accept, review, or reject?
› AI-powered. Deterministic by design.
AI interprets.
Deterministic code decides.
FHIR at Will uses an LLM where clinical language is ambiguous: extracting grounded facts from unstructured narrative. From there, explicit schemas, profiles, terminology rules, and validation logic control the result.
Grounded extraction
The LLM identifies clinical facts and ties them back to the source narrative.
FHIR assembly
Typed mappings turn extracted facts into predictable FHIR R4 resources and Bundles.
Deterministic verdict
The same facts, configuration, and rules produce the same validation outcome every time.
The boundary is explicit:
the model proposes meaning;
the platform enforces structure;
nothing is trusted without verification.
[ developers welcome ]
Built in the open.
Better with you.
Help shape practical, trustworthy healthcare interoperability. Contribute code, improve the docs, report issues, or bring a new idea.
- 01 Build features
- 02 Improve documentation
- 03 Report and fix issues
- 04 Share implementation ideas
[ one project · four services ]
Your own FHIR bridge.
One Railway deploy.
Launch the API, private HL7 validator, PostgreSQL, and Redis together. Generated secrets and database bootstrap are configured for you.
Deploy on Railway
- 01FHIR at Will APIPublic HTTPS endpoint
- 02HL7 ValidatorPrivate, pinned sidecar
- 03PostgreSQLRLS-enforced application role
- 04RedisPrivate cache and coordination