openapi: 3.1.0 info: title: NCI Clinical Search Diseases Trials API description: 'RESTful API for searching NCI-supported cancer clinical trials data sourced from NCI''s Clinical Trials Reporting Program (CTRP). This is the same API that powers NCI''s public Clinical Trials Search at cancer.gov. A free API key is required and must be sent in the X-API-KEY header; developers register through the CTS Developer Accounts portal at https://clinicaltrialsapi.cancer.gov/. This is a best-effort, hand-authored specification covering the documented v2 endpoints (trials, interventions, diseases, terms). Request and response payloads use permissive schemas where the full property set is not enumerated in public documentation. ' version: v2 contact: name: NCI Clinical Trials API url: https://clinicaltrialsapi.cancer.gov/ servers: - url: https://clinicaltrialsapi.cancer.gov/api/v2 security: - apiKey: [] tags: - name: Trials paths: /trials: get: tags: - Trials summary: Search clinical trials (GET form) description: 'Search for clinical trials using query-string parameters. Equivalent to POST /trials for simple queries. ' parameters: - in: query name: size schema: type: integer default: 10 - in: query name: from schema: type: integer default: 0 - in: query name: include description: Comma-separated fields to include in the response. schema: type: string - in: query name: exclude schema: type: string - in: query name: current_trial_status schema: type: string - in: query name: keyword schema: type: string responses: '200': description: Search results. content: application/json: schema: $ref: '#/components/schemas/TrialSearchResponse' post: tags: - Trials summary: Search clinical trials (POST form) description: 'Search for clinical trials with a full JSON query body supporting keyword, geographic, eligibility, biomarker, and other filters. ' requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/TrialSearchQuery' responses: '200': description: Search results. content: application/json: schema: $ref: '#/components/schemas/TrialSearchResponse' /trials/{id}: parameters: - in: path name: id required: true schema: type: string description: NCI trial id (e.g. NCI-2014-01632). get: tags: - Trials summary: Retrieve a single clinical trial responses: '200': description: Trial document. content: application/json: schema: $ref: '#/components/schemas/Trial' '404': description: Trial not found. components: schemas: Trial: type: object description: NCI clinical trial document. properties: nci_id: type: string nct_id: type: string brief_title: type: string official_title: type: string brief_summary: type: string current_trial_status: type: string phase: type: string study_protocol_type: type: string lead_org: type: string principal_investigator: type: string sites: type: array items: type: object additionalProperties: true eligibility: type: object additionalProperties: true diseases: type: array items: type: object additionalProperties: true interventions: type: array items: type: object additionalProperties: true additionalProperties: true TrialSearchQuery: type: object description: Free-form search query supported by the trials endpoint. properties: size: type: integer default: 10 from: type: integer default: 0 include: type: array items: type: string exclude: type: array items: type: string keyword: type: string current_trial_status: oneOf: - type: string - type: array items: type: string nci_id: type: array items: type: string nct_id: type: array items: type: string eligibility: type: object additionalProperties: true sites: type: object additionalProperties: true additionalProperties: true TrialSearchResponse: type: object properties: total: type: integer data: type: array items: $ref: '#/components/schemas/Trial' additionalProperties: true securitySchemes: apiKey: type: apiKey in: header name: X-API-KEY description: Free API key issued by the CTS Developer Accounts portal.