name: National Center for Biotechnology Information (NCBI)
description: >
  The National Center for Biotechnology Information (NCBI) provides a suite of
  free, publicly accessible REST APIs for querying and retrieving biological and
  biomedical data. Offerings include the Entrez Programming Utilities (E-utilities)
  for searching and fetching records across 38 databases including PubMed, GenBank,
  Gene, and Taxonomy; the BLAST URL API for homology sequence searching; the NCBI
  Datasets API for downloading genomic, gene, and taxonomy data; and PubChem APIs
  for chemical compound data. PMC developer tools provide Open Access article
  retrieval, metadata harvesting, identifier conversion, and citation export.
url: https://www.ncbi.nlm.nih.gov/home/develop/api/
image: https://www.ncbi.nlm.nih.gov/favicon.ico
tags:
  - Bioinformatics
  - Genomics
  - Life Sciences
  - PubMed
  - Sequences
  - BLAST
  - Taxonomy
  - Chemistry
  - Open Access
created: "2026-06-13"
modified: "2026-06-13"
specificationVersion: "0.19"
apis:

  - name: NCBI Entrez E-utilities API
    description: >
      The Entrez Programming Utilities (E-utilities) are the public API to the
      NCBI Entrez system, providing access to over 38 Entrez databases including
      PubMed, GenBank (Nuccore), Gene, Taxonomy, and Protein. Nine server-side
      programs support text search, record retrieval, batch download, database
      linking, spelling correction, and citation matching. Requests can be
      authenticated with an API key to raise rate limits from 3 to 10 requests
      per second.
    image: https://www.ncbi.nlm.nih.gov/favicon.ico
    humanURL: https://www.ncbi.nlm.nih.gov/books/NBK25497/
    baseURL: https://eutils.ncbi.nlm.nih.gov/entrez/eutils/
    tags:
      - Entrez
      - PubMed
      - GenBank
      - Gene
      - Taxonomy
      - Sequences
      - Literature
    properties:
      - type: documentation
        url: https://www.ncbi.nlm.nih.gov/books/NBK25497/
      - type: quickstart
        url: https://www.ncbi.nlm.nih.gov/books/NBK25500/
      - type: rate-limits
        url: https://kinlane.github.io/ncbi/rate-limits/e-utilities.yml
      - type: plans
        url: https://kinlane.github.io/ncbi/plans/e-utilities.yml
    contact:
      - FN: NCBI E-utilities Support
        email: vog.hin.mln.ibcn@seitilitue
        url: https://support.nlm.nih.gov/support/create-case/

  - name: NCBI BLAST URL API
    description: >
      The BLAST (Basic Local Alignment Search Tool) URL API allows developers
      to submit nucleotide and protein sequence homology searches via HTTPS,
      poll for job status, and retrieve results in multiple formats including
      XML, JSON, and tabular output. Jobs can be processed at NCBI or at cloud
      service providers. No API key is required, though responsible use
      guidelines apply.
    image: https://www.ncbi.nlm.nih.gov/favicon.ico
    humanURL: https://blast.ncbi.nlm.nih.gov/doc/blast-help/developerinfo.html
    baseURL: https://blast.ncbi.nlm.nih.gov/blast/Blast.cgi
    tags:
      - BLAST
      - Sequence Alignment
      - Homology
      - Genomics
    properties:
      - type: documentation
        url: https://blast.ncbi.nlm.nih.gov/doc/blast-help/developerinfo.html
      - type: rate-limits
        url: https://kinlane.github.io/ncbi/rate-limits/blast.yml
      - type: plans
        url: https://kinlane.github.io/ncbi/plans/blast.yml
    contact:
      - FN: NCBI BLAST Support
        url: https://support.nlm.nih.gov/support/create-case/

  - name: NCBI Datasets API
    description: >
      The NCBI Datasets v2 REST API, defined by an OpenAPI 3.0 specification,
      provides programmatic access to genomic sequences, gene records, taxonomy
      data, virus sequences, and ortholog information. It is the same API that
      powers the NCBI Datasets command-line tool and web interface. Data packages
      can be downloaded in zip archives containing FASTA, GFF3, and JSON summary
      files.
    image: https://www.ncbi.nlm.nih.gov/favicon.ico
    humanURL: https://www.ncbi.nlm.nih.gov/datasets/docs/v2/api/rest-api/
    baseURL: https://api.ncbi.nlm.nih.gov/datasets/v2
    tags:
      - Genomics
      - Gene
      - Taxonomy
      - Virus
      - Genome
    properties:
      - type: documentation
        url: https://www.ncbi.nlm.nih.gov/datasets/docs/v2/api/rest-api/
      - type: openapi
        url: https://raw.githubusercontent.com/ncbi/datasets/master/datasets.openapi.yaml
      - type: rate-limits
        url: https://kinlane.github.io/ncbi/rate-limits/datasets.yml
      - type: plans
        url: https://kinlane.github.io/ncbi/plans/datasets.yml
    contact:
      - FN: NCBI Datasets Support
        url: https://www.ncbi.nlm.nih.gov/datasets/docs/v2/troubleshooting/faq/

  - name: PubChem PUG REST API
    description: >
      The PubChem Power User Gateway (PUG) REST API provides programmatic
      access to PubChem's chemical compound, substance, and bioassay data.
      Developers can retrieve compound properties, structures, synonyms, and
      cross-references by name, SMILES, InChI, CID, SID, or AID. The API
      supports structure search operations and integrates with E-utilities
      for cross-database queries. Responses are available in JSON, XML,
      SDF, and other formats.
    image: https://pubchem.ncbi.nlm.nih.gov/favicon.ico
    humanURL: https://pubchem.ncbi.nlm.nih.gov/docs/pug-rest
    baseURL: https://pubchem.ncbi.nlm.nih.gov/rest/pug
    tags:
      - Chemistry
      - Compounds
      - PubChem
      - Structures
      - Bioassay
    properties:
      - type: documentation
        url: https://pubchem.ncbi.nlm.nih.gov/docs/pug-rest
      - type: rate-limits
        url: https://kinlane.github.io/ncbi/rate-limits/pubchem-pug-rest.yml
      - type: plans
        url: https://kinlane.github.io/ncbi/plans/pubchem-pug-rest.yml
    contact:
      - FN: PubChem Support
        url: https://pubchemdocs.ncbi.nlm.nih.gov/contact

  - name: PMC Open Access API (OA Service)
    description: >
      The PubMed Central Open Access API retrieves citation data, licensing
      details, and FTP download locations for Open Access articles in the PMC
      archive. Queries accept a PMC identifier and return structured XML with
      article metadata and links to full-text files in formats such as PDF and
      XML.
    image: https://pmc.ncbi.nlm.nih.gov/favicon.ico
    humanURL: https://pmc.ncbi.nlm.nih.gov/tools/oa-service/
    baseURL: https://www.ncbi.nlm.nih.gov/pmc/utils/oa/oa.fcgi
    tags:
      - PubMed Central
      - Open Access
      - Literature
      - PMC
    properties:
      - type: documentation
        url: https://pmc.ncbi.nlm.nih.gov/tools/oa-service/
      - type: rate-limits
        url: https://kinlane.github.io/ncbi/rate-limits/pmc-oa.yml
      - type: plans
        url: https://kinlane.github.io/ncbi/plans/pmc-oa.yml
    contact:
      - FN: PMC Support
        url: https://support.nlm.nih.gov/support/create-case/

  - name: PMC ID Converter API
    description: >
      The PMC ID Converter API translates between PubMed Central identifiers
      (PMCID), PubMed identifiers (PMID), Manuscript IDs, and Digital Object
      Identifiers (DOI). Batch conversion is supported, making it straightforward
      to harmonize identifiers across literature databases.
    image: https://pmc.ncbi.nlm.nih.gov/favicon.ico
    humanURL: https://pmc.ncbi.nlm.nih.gov/tools/id-converter-api/
    baseURL: https://pmc.ncbi.nlm.nih.gov/tools/idconv/api/v1/articles/
    tags:
      - PubMed Central
      - Identifiers
      - DOI
      - PMID
      - PMCID
    properties:
      - type: documentation
        url: https://pmc.ncbi.nlm.nih.gov/tools/id-converter-api/
      - type: rate-limits
        url: https://kinlane.github.io/ncbi/rate-limits/pmc-id-converter.yml
      - type: plans
        url: https://kinlane.github.io/ncbi/plans/pmc-id-converter.yml
    contact:
      - FN: PMC Support
        url: https://support.nlm.nih.gov/support/create-case/

  - name: PMC OAI-PMH Service
    description: >
      The PMC OAI-PMH (Open Archives Initiative Protocol for Metadata Harvesting)
      service allows bulk harvesting of metadata for all items in the PMC archive
      and full-text content for articles with Creative Commons licenses. It follows
      the OAI-PMH 2.0 protocol standard and is suited for building downstream
      literature indexes and research data pipelines.
    image: https://pmc.ncbi.nlm.nih.gov/favicon.ico
    humanURL: https://pmc.ncbi.nlm.nih.gov/tools/oai/
    baseURL: https://pmc.ncbi.nlm.nih.gov/api/oai/v1/mh/
    tags:
      - PubMed Central
      - OAI-PMH
      - Metadata Harvesting
      - Literature
      - Open Access
    properties:
      - type: documentation
        url: https://pmc.ncbi.nlm.nih.gov/tools/oai/
      - type: rate-limits
        url: https://kinlane.github.io/ncbi/rate-limits/pmc-oai-pmh.yml
      - type: plans
        url: https://kinlane.github.io/ncbi/plans/pmc-oai-pmh.yml
    contact:
      - FN: PMC Support
        url: https://support.nlm.nih.gov/support/create-case/

common:
  - type: authentication
    url: https://www.ncbi.nlm.nih.gov/account/
  - type: developer-portal
    url: https://www.ncbi.nlm.nih.gov/home/develop/
  - type: terms-of-service
    url: https://www.ncbi.nlm.nih.gov/home/about/policies/
  - type: support
    url: https://support.nlm.nih.gov/support/create-case/
  - type: status
    url: https://ncbiinsights.ncbi.nlm.nih.gov/
  - type: blog
    url: https://ncbiinsights.ncbi.nlm.nih.gov/
  - type: twitter
    url: https://twitter.com/NCBI
  - type: youtube
    url: https://www.youtube.com/user/NCBINLM
  - type: finops
    url: https://kinlane.github.io/ncbi/finops/overview.yml

maintainers:
  - FN: Kin Lane
    email: kin@apievangelist.com