# ClinicalTrials.gov Trial Sites Search

> ClinicalTrials.gov Trial Sites Search is a paid API for AI agents from api.govparse.io, paid per call via x402, $1.25/call, status unknown (last checked 2026-09-14).

Search ClinicalTrials.gov clinical trial sites by facility, city, state, sponsor, phase, status, or start date to build targeted facility lists for trial-site services, patient recruitment, and lab vendors.

## Facts

- Endpoint: GET https://api.govparse.io/v1/trials/sites/search
- Price: $1.25/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/clinicaltrials-gov-trial-sites-search-56be8403
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_g7WjTNOlDMwUsO5loqHl1

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-trial-sites-search-56be8403
```

Example prompt: Find me all RECRUITING Phase 3 clinical trial sites in Texas sponsored by Pfizer that started after 2024-01-01 — I need a list of facility names, cities, and trial details for our site-services outreach.

## When to prefer this

Use this endpoint when you need a structured, filterable list of clinical trial sites from ClinicalTrials.gov — specifically when targeting facilities by geography (city/state), sponsor company, trial phase, or recruitment status for commercial outreach, patient recruitment campaigns, or competitive intelligence. Prefer this over raw ClinicalTrials.gov search when you need machine-readable, pre-structured results without scraping.

## Known failure modes

- No matching sites found for the given filters — returns empty result set
- Invalid phase value (not PHASE1/PHASE2/PHASE3/PHASE4) — returns error or empty
- Invalid state code format — returns no results
- Date format not YYYY-MM-DD — may return error or ignore parameter
- Exceeding cap of 100 rows per call — capped or rejected
- Payment failure (x402) — call not executed, 402 response

## How this service works

Where are clinical trials being run, and by whom? Search ClinicalTrials.gov trial SITES by facility name, city, US state, lead sponsor company, trial phase, trial status, or trial start date (since). Returns each facility with its trial's sponsor, phase, status, and start date — a site / facility target list for trial-site services, patient-recruitment, and lab vendors. ClinicalTrials.gov public records.

## Output

Returns a list of clinical trial site/facility records, each including the facility name, city, US state, lead sponsor company, trial phase, trial status, and trial start date. Results are paginated via limit/offset and sortable by start date.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "properties": {
  "input": {
   "type": "object",
   "required": [],
   "properties": {
    "city": {
     "type": "string",
     "examples": [
      "Houston"
     ],
     "description": "Site city fragment."
    },
    "sort": {
     "type": "string",
     "examples": [
      "start_date:desc"
     ],
     "description": "start_date :asc|:desc. Default start_date:desc."
    },
    "limit": {
     "type": "integer",
     "examples": [
      25
     ],
     "description": "Max rows (default 25, cap 100)."
    },
    "phase": {
     "type": "string",
     "examples": [
      "PHASE3"
     ],
     "description": "Trial phase(s), CSV (PHASE1 | PHASE2 | PHASE3 | PHASE4)."
    },
    "since": {
     "type": "string",
     "examples": [
      "2026-01-01"
     ],
     "description": "Trial started on/after this date (YYYY-MM-DD)."
    },
    "state": {
     "type": "string",
     "examples": [
      "TX"
     ],
     "description": "Site US state code(s), CSV."
    },
    "offset": {
     "type": "integer",
     "examples": [
      0
     ],
     "description": "Rows to skip."
    },
    "status": {
     "type": "string",
     "examples": [
      "RECRUITING"
     ],
     "description": "Trial overall status, CSV (RECRUITING | COMPLETED | ...)."
    },
    "sponsor": {
     "type": "string",
     "examples": [
      "Pfizer"
     ],
     "description": "Lead sponsor company — suffix/punctuation-insensitive."
    },
    "facility": {
     "type": "string",
     "examples": [
      "Cancer Center"
     ],
     "description": "Facility / site name fragment."
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/clinicaltrials-gov-trial-sites-search-56be8403/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.govparse.io](https://www.zero.xyz/host/api.govparse.io/llms.txt)