# FHIR Observation by Category

> FHIR Observation by Category is a paid API for AI agents from clonecho.builda.company, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-15).

Lists FHIR R4 Observation resources from the public HL7 test server filtered by a specified category code

## Facts

- Endpoint: POST https://clonecho.builda.company/x402/s/fhir-observation-by-category
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fhir-observation-by-category-83c2041c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_P5u0YlM5gAw3vTUcVWdHK

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-observation-by-category-83c2041c -d '<json body>'
```

Example prompt: Can you pull all FHIR Observation resources in the 'vital-signs' category from the public HL7 FHIR R4 test server?

## When to prefer this

Use this endpoint when you need to retrieve FHIR R4 Observation resources filtered by a known category (e.g. 'vital-signs', 'laboratory', 'social-history') from the public HL7 FHIR R4 test server, particularly for prototyping, testing FHIR integrations, or exploring clinical observation data structures without setting up your own FHIR server.

## Known failure modes

- Invalid or unrecognized category code returns empty bundle or 400 error
- Public FHIR test server may be temporarily unavailable causing timeout or 5xx response
- Category parameter missing returns error or unfiltered/unexpected results
- Very broad category with many results may cause slow response or truncation

## How this service works

List FHIR Observation resources filtered by category {q} from the public HL7 FHIR R4 test server. Query: ?q= Returns JSON.

## Output

A JSON array of FHIR R4 Observation resources matching the specified category, including fields like subject, code, value, effectiveDateTime, and status as returned by the public HL7 FHIR R4 test server.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fhir-observation-by-category-83c2041c/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)