# FHIR R4 StructureDefinition List

> FHIR R4 StructureDefinition List is a paid API for AI agents from clonecho.builda.company, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).

Lists FHIR profiles and StructureDefinition resources from the public HL7 FHIR R4 test server, returning a configurable number of entries as a FHIR Bundle JSON.

## Facts

- Endpoint: POST https://clonecho.builda.company/x402/s/fhir-structure-definition-list
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fhir-r4-structuredefinition-list-4e4f40aa
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_MCW7gLptr96j0TjTdUi6O

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability fhir-r4-structuredefinition-list-4e4f40aa -d '<json body>'
```

Example prompt: Can you pull me a list of 20 FHIR StructureDefinition profiles from the HL7 FHIR R4 test server and return them as a FHIR Bundle?

## When to prefer this

Use this endpoint when you need to enumerate or browse available FHIR profiles and StructureDefinition resources from the HL7 FHIR R4 public test server. Prefer this over direct FHIR server queries when you need a simple, paid-API abstraction that returns a clean JSON FHIR Bundle without managing FHIR server authentication or pagination complexity.

## Known failure modes

- Invalid or missing q parameter may return an empty or default-sized bundle
- HL7 FHIR R4 public test server downtime may cause request failure
- Non-numeric q value may result in a bad request error
- Very large q values may time out or be capped by the upstream server

## How this service works

List FHIR profiles and structure definitions (StructureDefinition resources) from the public HL7 FHIR R4 test server, returning {q} entries as a FHIR Bundle. Query: ?q= Returns JSON.

## Output

A FHIR Bundle (JSON) containing the requested number of StructureDefinition resources, each describing a FHIR profile or structure definition from the public HL7 FHIR R4 test server.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fhir-r4-structuredefinition-list-4e4f40aa/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from clonecho.builda.company](https://www.zero.xyz/host/clonecho.builda.company/llms.txt)