FHIR REST API

Every FHIR server exposes the same surface:

GET /Patient/123 read

POST /Patient create

PUT /Patient/123 update (replace)

PATCH /Patient/123 partial update

DELETE /Patient/123 delete

GET /Patient?name=Smith&_count=10 search

POST / transaction bundle

GET /metadata capability statement

For agentic builders, the bundle pattern is gold: assemble multiple resource creates/updates with cross-references using urn:uuid:... and send as one transaction.

Pagination: response Bundles include link entries with relation: "next". Always follow until empty.

Auth: in production almost always SMART-on-FHIR OAuth 2.0. Synthea / Medplum sandboxes are open for dev.