FHIR JSON utility
Compare two FHIR resources or Bundles and find meaningful changes by resource, JSON path, semantic array identity, and reference target.
Comparison
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.
Baseline or before version.
Changed or after version.
| Status | Resource | Path | Original | Updated |
|---|
A differences-only report will appear here.
FAQ
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.
Those server-managed metadata values commonly change even when the meaningful resource content is otherwise equivalent. You can include them by clearing the options.
No. It compares JSON structure and applies practical FHIR-aware matching, but it does not validate profiles, terminology bindings, invariants, or implementation guides.
No. Use synthetic or appropriately de-identified test data only.
Practical guide
The comparison tool is intended for release testing, interface troubleshooting, regression review, and examining before-and-after resources. It compares parsed JSON structure, so indentation and property order should not distract from actual value, resource, and repeating-element changes.
Worked example
Before: Observation.status = "preliminary"
After: Observation.status = "final"
Before: Observation.valueQuantity.value = 4.8
After: Observation.valueQuantity.value = 5.6The first change represents workflow state; the second changes the reported measurement. Both may be legitimate, but they deserve different review. A regression test might permit the status transition while requiring explicit confirmation that the changed result was expected.
Also inspect related fields such as effectiveDateTime, issued, reference ranges, interpretation codes, units, and the coding system. A numeric value that appears unchanged can still mean something different when its unit or code changes.
Interpreting differences
FHIR arrays are often conceptually matched by stable properties such as system, value, code, or resource ID rather than by visual position alone. Missing stable keys or regenerated IDs can make two equivalent-looking collections harder to match.
When a system changes array ordering on every response, normalize or stabilise the test data before deciding that every reported movement is a defect.
Authorship and review
Maintained and technically reviewed by Health Data Tools, drawing on more than 15 years of healthcare integration experience across HL7, FHIR, CDA, APIs, PKI, and clinical integration systems.
Technically reviewed:
Official references
These references support the technical context. Local implementation guides, vendor profiles, and receiving-system rules still take precedence for a specific interface.