Endpoint liveness
What share of FHIR-REST endpoints in the NPD are actually reachable, parseable, and SMART-capable? Scored L0 through L7 per the ainpi-probe crawler.
Headline
Full crawl of 2,974 distinct FHIR-REST hosts in the NDH: 93.3% answered HTTP, 85.4% served a parseable CapabilityStatement, 81.6% published valid SMART well-known, 90.3% answered an unauthenticated Practitioner?_count=1 with 200/401. Across the full NDH endpoint population: 5,043,524 endpoints total (74.2% FHIR-REST, 25.8% Direct Project); 98.7% of Organizations carry zero Endpoint references.
2.5K / 3.0K = 85.37%
unit: percent
What this means
Payer data teams
If you build integrations against declared NDH FHIR endpoints, expect 14.6% to fail at /metadata and 18.4% to lack a valid SMART well-known — budget for partial availability rather than treating endpoint presence as functional.
Provider data teams
An endpoint URL in NDH does not prove your endpoint works. Audit yours against ainpi-probe L0–L7: DNS, TLS cert expiry, CapabilityStatement conformance, SMART discovery, unauthenticated Practitioner search.
Regulators
Technical reachability (90.4% L7) vs SMART discovery compliance (81.6%) is a 9-point gap. If rules start citing SMART conformance, current NDH is below the implied bar.
FHIR implementers
Zero R5 endpoints, zero R2 — NDH is a pure R4 population. Don’t spend cycles on R5 compatibility testing for this directory.
Null hypothesis
FHIR-REST endpoints are reachable and conformant at or above the implied 85% network-adequacy ceiling.
Denominator
All `Endpoint` resources with `connectionType` in the FHIR-REST family.
Data source
CMS NPD bulk export + live HTTP probes run by the `ainpi-probe` crawler against declared `Endpoint.address` URLs.
Notes
Probed 2,974 distinct FHIR-REST hosts (one endpoint per host, stratified by host). Crawl: 16 global concurrency, 1 rps per host, 10s connect / 30s read, exponential backoff on 429/503, User-Agent AINPI-DirectoryQualityBot/1.0. fhirVersion declared by L5-conformant hosts: {'4.0.1': 1599, '4.0.0': 938, '3.0.2': 1, '3.0.1': 1}. CapabilityStatement software top-5: {'Firely Server': 505, 'Epic': 456, 'Fhir Server': 282, 'Altera FHIR': 71, '1up FHIR Server': 42}. Highest level reached distribution: {7: 2687, 0: 33, -1: 136, 1: 23, 2: 28, 3: 39, 6: 14, 5: 14}. Certs expiring within 90 days of release: 271. H4 (connection type distribution) and H5 (orgs without endpoints) computed over the full population in BigQuery: H4 connection types: {'hl7-fhir-rest': 3741547, 'direct-project': 1301977}; H5 3,603,262 orgs of which 3,556,049 have no managingOrganization reference from any Endpoint.