fhir-resource-diff

Diff, validate, and inspect FHIR resources. Fast. Local. CI-ready.

Path-level diff

Compare two FHIR resources field by field. Every added, removed, and changed value is tracked with dot-notation paths and array index tracking — including nested CodeableConcepts, extensions, and identifiers.

Structured validation

Catch common FHIR mistakes before submission — id format, date patterns, reference string shape, known resource types — with severity levels (error, warning, info) and links to HL7 documentation.

CI/CD native

--exit-on-diff fails a build step when resources diverge. --quiet suppresses stdout for exit-code-only gates. --envelope wraps output in a metadata envelope for automated triage. Exit codes are severity-aware.

AI agent friendly

Every command supports stdin pipes, --format json for structured output, and --envelope for metadata wrapping with tool version, FHIR version, timestamps, and HL7 doc URLs. No temp files, one pass.

fhir-resource-diff is a CLI and TypeScript library for working with FHIR JSON resources locally — no server, no Java runtime, no package downloads. It compares resources path by path, validates format and structure, normalizes for comparison, and exposes a browser-safe API for use in React, Vite, and any bundler.

Supports FHIR R4, R4B, and R5 — auto-detected or explicit via --fhir-version.

bash

# Install
npm install -g fhir-resource-diff

# Validate a resource
fhir-resource-diff validate patient.json --fhir-version R4

# Compare two resources
fhir-resource-diff compare expected.json actual.json

# Diff with JSON output for automation
fhir-resource-diff compare a.json b.json --format json --envelope