# ClinicalTrials.gov Study Lookup via x402

> ClinicalTrials.gov Study Lookup via x402 is a paid API for AI agents from x402helper.xyz, paid per call via x402, $0.026/call, status unknown (last checked 2026-11-07).

Retrieves clinical trial study data from ClinicalTrials.gov by NCT ID, paid via x402 USDC micropayment.

## Facts

- Endpoint: GET https://x402helper.xyz/89e509/trials/study?utm_source=zero.xyz
- Price: $0.026/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-07
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/clinicaltrials-gov-study-lookup-via-x402-dfd15e44
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_TZHORbzed0WyP5AomifV7

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 clinicaltrials-gov-study-lookup-via-x402-dfd15e44
```

Example prompt: Can you look up the clinical trial NCT03228186 and tell me what it's studying, its phase, and current status?

## When to prefer this

Use this endpoint when you need programmatic, pay-per-call access to ClinicalTrials.gov study records by NCT ID and are operating in an x402 USDC micropayment environment. Prefer this over direct ClinicalTrials.gov API calls when you need a metered, agent-friendly interface with x402 payment rails built in.

## Known failure modes

- Invalid or non-existent NCT ID returns empty or error result
- Missing required 'input' field returns schema validation error
- Payment failure via x402 results in 402 Payment Required response before data is returned
- Network timeout if ClinicalTrials.gov upstream is slow

## How this service works

X402 micropayments server — AI agents pay USDC for OFAC screening, rates, and billing verification.

## Output

Returns a JSON object with a success flag and a result object containing clinical trial study data from ClinicalTrials.gov corresponding to the provided NCT ID, such as trial title, phase, status, sponsor, conditions, and outcomes.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "id": {
       "type": "string",
       "default": null,
       "description": "Alias for nct"
      },
      "nct": {
       "type": "string",
       "default": null,
       "description": "A ClinicalTrials.gov NCT id such as NCT03228186"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {},
  "success": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/clinicaltrials-gov-study-lookup-via-x402-dfd15e44/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402helper.xyz](https://www.zero.xyz/host/x402helper.xyz/llms.txt)