API Reference
The Huli API is a standards-based FHIR REST surface — the safest bet for an EHR, lab, or billing integration. Read and write real clinical data through the same FHIR resources your existing tools already speak, with one OAuth flow and one scope model across both FHIR R4 and R5.
One standard FHIR Patient resource is consumed by every system a clinic integration touches — your EHR, lab systems, billing, and your AI agent. Because each already speaks FHIR, there is no per-vendor mapping layer to build: adopt the standard once and everything downstream already understands it.
Why FHIR first
FHIR is the data model the healthcare integrator community already runs on. Adopt it once and every downstream system — EHR, HIE, lab, billing, and your own AI agent — understands your data without a per-vendor adapter. Every resource here maps a standard FHIR shape to the underlying HuliPractice record; a couple of endpoints (authentication, capability discovery) are plain REST and clearly marked.
Both FHIR R4 (the stable default) and FHIR R5 are served side by side — same token, same scopes, same pagination. Switch releases with the R4 / R5 control in the sidebar, or from the switch on any resource page.
Explore the API
Browse FHIR resources
Every R4 and R5 resource — Patient, Appointment, Encounter, Observation, and more — with interactions, scopes, and search parameters.
/v1/api/resources →Authentication
SMART Backend Services — client_credentials with private_key_jwt, plus admin bearer keys to start fast.
POST /auth/token →Scopes
The least-privilege system/Resource.* access model, shared identically across both releases.
system/Patient.rs →Errors
Every failure is a FHIR OperationOutcome carrying a stable HPB- code — branch on it, no string matching.
HPB-00101 →Choosing R4 vs R5
What differs between the two releases, and which one to target for your integration.
R4 · R5 →