clinicaltrials-api-v2

# ClinicalTrials.gov v2 API Guide ## Overview ClinicalTrials.gov is the world's largest clinical trial registry, maintained by the U.S. National Library of Medicine (NLM) at NIH. It contains over 576,000 study records from 220+ countries covering interventional trials, observational studies, and expanded access programs. The v2 API provides structured JSON access with field-level filtering, cursor-based pagination, and statistics endpoints. Key v2 improvements over the legacy API: JSON-native responses, sparse field selection via the `fields` parameter, `nextPageToken` pagination, and dedicated statistics endpoints. Study data is organized into `protocolSection` (sponsor-submitted) and `derivedSection` (NLM-computed). ## Authentication No authentication required. All endpoints are publicly accessible without API keys or registration. Users should comply with NCBI usage policies and maintain reasonable request rates. ## Core Endpoints ### Search Studies - **URL**: `GET https://clinicaltrials.gov/api/v2/studies` - **Parameters**: | Parameter | Type | Required | Description | |-----------|------|----------|-------------| | query.term | string | No | Free-text search across all fields | | query.cond | string | No | Condition or disease filter | | query.intr | string | No | Intervention or treatment filter | | query.spons | string | No | Sponsor or collaborator filter | | filter.overallStatus | string | No | `RECRUITING`, `COMPLETED`, `ACTIVE_NOT_RECRUITING`, etc. | | fil...