FHIR JSON utility

FHIR Resource Diff & Comparison Tool

Compare two FHIR resources or Bundles and find meaningful changes by resource, JSON path, semantic array identity, and reference target.

Compare FHIR Open FHIR viewer Generate sample FHIR

Patient.name[official].family
OBrien → McCarthy

Observation/observation-001
valueQuantity.value
6.2 → 7.4

+ Observation/observation-002

Privacy reminder. Do not paste real patient data, credentials, secrets, production identifiers, or confidential resources. Use synthetic or properly de-identified test data only.

Comparison

Paste two FHIR resources or Bundles

The comparison runs locally in your browser. Common repeating elements and Bundle entries are matched using meaningful FHIR identifiers where possible rather than array position alone.

Original FHIR JSON

Baseline or before version.

Updated FHIR JSON

Changed or after version.

Comparison options

Ignore meta.lastUpdated Ignore meta.versionId Ignore narrative text.div Match repeating elements semantically Ignore whitespace differences Case-sensitive comparison Show unchanged values

Additional ignored paths

Separate paths with commas or spaces. Asterisks act as wildcards.

A differences-only report will appear here.

FAQ

FHIR comparison questions

How are repeating elements matched?

The tool uses FHIR-aware keys where possible: identifier by system and value, coding by system and code, extension by URL, telecom by system and use, names by use and name content, references by target, and Bundle entries by fullUrl or resourceType/id. It falls back to array order when a stable key is unavailable.

Why are meta.lastUpdated and meta.versionId ignored by default?

Those server-managed metadata values commonly change even when the meaningful resource content is otherwise equivalent. You can include them by clearing the options.

Does this validate FHIR conformance?

No. It compares JSON structure and applies practical FHIR-aware matching, but it does not validate profiles, terminology bindings, invariants, or implementation guides.

Can I paste real patient data?

No. Use synthetic or appropriately de-identified test data only.