Implementation guides are how FHIR becomes specific. Every serious FHIR program ends up writing or consuming an IG, and conformance testing against that IG is the discipline that separates a working integration from a hopeful one. A validat

Open-source validators are where most FHIR programs start, and where many of them stay. The category has matured into a stable shortlist where each tool covers a recognizable use case, and the gaps between them are clear enough to make a pi

US Core conformance is the validation case most US-facing FHIR programs care about. The profile set is the baseline for ONC certification, payer-side ingestion, and any data-sharing pathway that ends in a national HIE. A validator that gets

A FHIR validator is the part of a FHIR stack that is easy to ignore until a payer rejects a batch of submissions. Validation sits between authoring and persistence, and it is the only layer that actually enforces whether a resource conforms