United States National Library of Medicine

United States National Library of Medicine Metadata API

API metadata and field definitions

Documentation GitHub OpenAPI

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OpenAPI Specification

openapi: 3.0.3
info:
  title: NCBI URL BLAST Metadata API
  description: 'The NCBI BLAST URL API allows developers to submit BLAST (Basic Local Alignment Search Tool) sequence searches for processing at NCBI using HTTPS. The API operates in three phases: (1) PUT request to submit a search and receive a request ID (RID), (2) polling GET requests to check search status, (3) GET request to retrieve results in the desired format. Supports nucleotide (blastn, blastx) and protein (blastp, tblastn, tblastx) searches.'
  version: 1.0.0
  contact:
    name: NCBI BLAST
    url: https://blast.ncbi.nlm.nih.gov/doc/blast-help/developerinfo.html
  license:
    name: Public Domain
    url: https://www.usa.gov/government-works
servers:
- url: https://blast.ncbi.nlm.nih.gov/blast
  description: NCBI BLAST Server
tags:
- name: Metadata
  description: API metadata and field definitions
paths:
  /stats/size:
    get:
      operationId: getDatasetSize
      summary: Get Dataset Size
      description: Returns the total number of clinical trials in the ClinicalTrials.gov database, optionally filtered by query parameters.
      tags:
      - Metadata
      parameters:
      - name: query.cond
        in: query
        required: false
        schema:
          type: string
      - name: filter.overallStatus
        in: query
        required: false
        schema:
          type: string
      responses:
        '200':
          description: Total count of matching studies
          content:
            application/json:
              schema:
                type: object
                properties:
                  totalCount:
                    type: integer
                    description: Total number of studies matching the query
  /studies/metadata:
    get:
      operationId: getStudyFieldsMetadata
      summary: Get Study Fields Metadata
      description: Retrieve metadata about all available data fields in the ClinicalTrials.gov study record, including field names, types, and descriptions.
      tags:
      - Metadata
      responses:
        '200':
          description: Study field metadata
          content:
            application/json:
              schema:
                type: object