Terminology Service
Terminology Service
Every coded thing on the rail resolves here: what a code means, whether it is still valid, what it belongs to, what it maps to, and what it costs.
Grouped by the question being asked rather than by resource — discovery, concepts, FHIR operations, value sets, versioned reads, benefits and rates, search and export.
Two things before any call. Authentication is a token and nothing else: the service reads the realm from the token itself, so there is no variant or tenant header to guess at. And anonymous is a real access level — discovery and search answer with no credential, returning only what is published publicly.
Taught at the terminology service.
Tags
Discovery
What exists, and who this token is. Most of this group answers without a credential, which makes it the quickest way to confirm a short code instead of guessing it. Taught in The terminology service.
Concepts
Reading one code, and walking the tree it sits in. Hierarchy is served from a closure table — do not assemble it yourself. Taught in Walking a concept tree.
FHIR operations
Code in, answer out. All are
GET, all return a FHIR Parameters resource, and all are version-aware. Taught in Validating a code.Value sets
Membership, and why a code is in it. Poll staleness rather than re-expanding on a schedule.
Concept maps
Translating a code from one vocabulary into another — the ICD-11 to ICD-10 crosswalk and everything shaped like it. Taught in Translating between vocabularies.
Versioned reads
How you stop a vocabulary change from becoming an incident. This is the group that matters most once you are live. Taught in Pinning to a release.
Benefits and rates
The two groups you meet on the rail rather than in a general terminology client. Benefits resolve in layers; rates are release-gated. Taught in What a cover pays for.
Getting the data out
Four shapes of the same terminology: paged JSON for a running integration, FHIR for a terminology client, and CSV or Excel for a human. Taught in Getting the data you need.
Search
Finding something when you do not know which system it is in.