What is FHIR's Capability Statement? Explaining the Mechanism for Exposing Server Functionality
Capability Statement (FHIR Capability Statement) - FirestarterPro
Summary
A FHIR Capability Statement is a machine-readable document published by a FHIR server or client that declares which resource types, operations, and profiles it supports. This allows users to programmatically confirm the API contract beforehand.
Details
The CapabilityStatement resource must be published by every FHIR server at a standard endpoint (GET [base]/metadata). It acts like an explicit API contract, defining what the server is capable of doing. Previously, determining server functionality required reading documentation or experimental probing. With the CapabilityStatement, clients can programmatically discover supported resources (e.g., Patient), operations (read, search-type), and search parameters (identifier, birthdate) before making requests. This capability is crucial as the FHIR ecosystem matures. This mechanism is utilized in various integration contexts, such as ONC certification testing and SMART App Launch discovery. By structuring server metadata alongside supported resources and profiles, it contributes to automated test plan generation and improved reliability in system integration.
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