FHIR Resource Visualizer

Visualize FHIR resources as an interactive tree. Inspect nested elements, references, and extensions privately in your browser.

  • Explore any FHIR resource or Bundle as a collapsible tree.
  • Inspect nested elements, extensions, and references without scrolling raw JSON.

How to use the tree visualizer

  1. Paste any FHIR resource or Bundle, drop a .json file, or open one from your workspace.
  2. Expand and collapse nodes to explore the structure. Values are colour-coded by JSON type (strings, numbers, booleans, null), and key FHIR elements such as resourceType, id, reference and identifier are highlighted.
  3. Use Search to find any key or value. Matching nodes are highlighted, so you can spot, for example, every reference in a large Bundle. The first two levels are expanded to start with; expand deeper branches to reach matches inside them.

Everything runs in your browser and nothing is uploaded.

When a tree beats raw JSON

  • Large Bundles. A searchset with 50 entries is thousands of lines of JSON. Collapsed, it's 50 lines, one per entry, and you can expand just the one you need.
  • Deep nesting. Observation components, extensions inside extensions, and contained resources are easier to follow as indented branches than as matching braces.
  • Finding where data lives. Search for 8480-6 and the highlighted node shows it sits under component → code → coding → code, which is the path you need for a FHIRPath expression or a mapping.
  • Reviewing what you're about to share. Expanding a resource fully is a quick way to spot names, dates and identifiers hiding in notes or extensions before you send a sample to someone.

Worked example

Paste this Bundle and search for reference:

{
  "resourceType": "Bundle",
  "type": "collection",
  "entry": [
    { "fullUrl": "urn:uuid:p1", "resource": { "resourceType": "Patient", "id": "p1", "name": [{ "family": "Shaw" }] } },
    { "fullUrl": "urn:uuid:o1", "resource": {
        "resourceType": "Observation", "id": "o1", "status": "final",
        "code": { "coding": [{ "system": "http://loinc.org", "code": "8867-4" }] },
        "subject": { "reference": "Patient/p1" },
        "valueQuantity": { "value": 72, "unit": "/min" } } }
  ]
}

The reference key under entry[1].resource.subject is highlighted. It's the only reference in the Bundle. To check whether references like this resolve to entries in the Bundle, use the Reference Resolver.

Limitations

  • The tree shows the JSON structure as written. It doesn't validate it: misspelled elements appear like any other key. Run the Validator for that.
  • To see what the specification says about an element (type, cardinality, definition), use the Resource Inspector.
  • Input must be valid JSON. If parsing fails, the JSON Prettifier points to the line with the problem.

FAQ

Does it work with any resource type?

Yes. The tree works with any JSON, so every FHIR resource type and version displays correctly, including custom extensions.

Can I edit values in the tree?

No. The tree is read-only. Edit the JSON in the input panel and the tree updates.

Is my data uploaded?

No. The tree is built from your JSON in this page.

Which FHIR versions does it support?

All of them. The tree shows whatever elements are present, including extensions, in R4, R4B or R5.

FHIR Toolbox is a free collection of HL7 FHIR tools by Omindra Labs. The tools process your data in your browser; it is not uploaded for normal tool operations.