National Center for Biotechnology Information (NCBI)

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/
accessModel:
  pricing: free
  onboarding: open
  trial: false
  try_now: true
  public: true
  label: Free · Open access
  confidence: high
  source:
  - plans
  - authentication
  generated: '2026-07-22'
  method: derived
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: GettingStarted
    url: https://www.ncbi.nlm.nih.gov/books/NBK25500/
  - type: RateLimits
    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: RateLimits
    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: 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: RateLimits
    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: RateLimits
    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: RateLimits
    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: RateLimits
    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/
- aid: ncbi:ncbi-biosample-api
  name: National Center for Biotechnology Information (NCBI) BioSample API
  description: '#### Options to download BioSample data.

    This BioSample service allows you to get BioSample data as a data report.'
  humanURL: https://www.ncbi.nlm.nih.gov/books/NBK25497/
  baseURL: https://eutils.ncbi.nlm.nih.gov/entrez/eutils/
  tags:
  - BioSample
  properties:
  - type: OpenAPI
    url: openapi/ncbi-biosample-api-openapi.yml
  - type: Documentation
    url: https://www.ncbi.nlm.nih.gov/datasets/docs/v2/api/rest-api/
  - type: RateLimits
    url: https://kinlane.github.io/ncbi/rate-limits/datasets.yml
  - type: Plans
    url: https://kinlane.github.io/ncbi/plans/datasets.yml
- aid: ncbi:ncbi-gene-api
  name: National Center for Biotechnology Information (NCBI) Gene API
  description: '#### Options to download gene data, including the associated sequence and metadata.

    These gene services allow you to get gene metadata as a data report or download gene, transcript and protein sequence,
    and metadata, as a gene data package, for all genes in NCBI Gene.'
  humanURL: https://www.ncbi.nlm.nih.gov/books/NBK25497/
  baseURL: https://eutils.ncbi.nlm.nih.gov/entrez/eutils/
  tags:
  - Gene
  properties:
  - type: OpenAPI
    url: openapi/ncbi-gene-api-openapi.yml
  - type: Documentation
    url: https://www.ncbi.nlm.nih.gov/datasets/docs/v2/api/rest-api/
  - type: RateLimits
    url: https://kinlane.github.io/ncbi/rate-limits/datasets.yml
  - type: Plans
    url: https://kinlane.github.io/ncbi/plans/datasets.yml
- aid: ncbi:ncbi-genome-api
  name: National Center for Biotechnology Information (NCBI) Genome API
  description: '#### Options to download assembled genome data, including the associated sequence, annotation and metadata.

    These genome services allow you to get genome metadata as a data report or download genome, transcript and protein sequence,
    annotation and metadata as a genome data package, for assembled genomes.'
  humanURL: https://www.ncbi.nlm.nih.gov/books/NBK25497/
  baseURL: https://eutils.ncbi.nlm.nih.gov/entrez/eutils/
  tags:
  - Genome
  properties:
  - type: OpenAPI
    url: openapi/ncbi-genome-api-openapi.yml
  - type: Documentation
    url: https://www.ncbi.nlm.nih.gov/datasets/docs/v2/api/rest-api/
  - type: RateLimits
    url: https://kinlane.github.io/ncbi/rate-limits/datasets.yml
  - type: Plans
    url: https://kinlane.github.io/ncbi/plans/datasets.yml
- aid: ncbi:ncbi-organelle-api
  name: National Center for Biotechnology Information (NCBI) Organelle API
  description: '#### Options to download RefSeq organelle genome data, including the associated sequence and metadata.

    These organelle services allow you to get RefSeq organelle genome metadata as a data report or download gene, transcript
    and protein sequence, and metadata, as an organelle data package, for RefSeq organelle genomes.'
  humanURL: https://www.ncbi.nlm.nih.gov/books/NBK25497/
  baseURL: https://eutils.ncbi.nlm.nih.gov/entrez/eutils/
  tags:
  - Organelle
  properties:
  - type: OpenAPI
    url: openapi/ncbi-organelle-api-openapi.yml
  - type: Documentation
    url: https://www.ncbi.nlm.nih.gov/datasets/docs/v2/api/rest-api/
  - type: RateLimits
    url: https://kinlane.github.io/ncbi/rate-limits/datasets.yml
  - type: Plans
    url: https://kinlane.github.io/ncbi/plans/datasets.yml
- aid: ncbi:ncbi-prokaryote-api
  name: National Center for Biotechnology Information (NCBI) Prokaryote API
  description: '#### Options to download prokaryote gene data, including the associated sequence and metadata.

    These gene services allow you to download gene and protein sequence, and metadata as a prokaryote gene data package, for
    prokaryotic [RefSeq non-redundant proteins](https://www.ncbi.nlm.nih.gov/refseq/about/nonredundantproteins/).'
  humanURL: https://www.ncbi.nlm.nih.gov/books/NBK25497/
  baseURL: https://eutils.ncbi.nlm.nih.gov/entrez/eutils/
  tags:
  - Prokaryote
  properties:
  - type: OpenAPI
    url: openapi/ncbi-prokaryote-api-openapi.yml
  - type: Documentation
    url: https://www.ncbi.nlm.nih.gov/datasets/docs/v2/api/rest-api/
  - type: RateLimits
    url: https://kinlane.github.io/ncbi/rate-limits/datasets.yml
  - type: Plans
    url: https://kinlane.github.io/ncbi/plans/datasets.yml
- aid: ncbi:ncbi-taxonomy-api
  name: National Center for Biotechnology Information (NCBI) Taxonomy API
  description: '#### Options to download taxonomy data.

    These taxonomy services allow you to get taxonomy data as a data report or download taxonomy data as a taxonomy data package,
    for taxonomic nodes in NCBI Taxonomy.'
  humanURL: https://www.ncbi.nlm.nih.gov/books/NBK25497/
  baseURL: https://eutils.ncbi.nlm.nih.gov/entrez/eutils/
  tags:
  - Taxonomy
  properties:
  - type: OpenAPI
    url: openapi/ncbi-taxonomy-api-openapi.yml
  - type: Documentation
    url: https://www.ncbi.nlm.nih.gov/datasets/docs/v2/api/rest-api/
  - type: RateLimits
    url: https://kinlane.github.io/ncbi/rate-limits/datasets.yml
  - type: Plans
    url: https://kinlane.github.io/ncbi/plans/datasets.yml
- aid: ncbi:ncbi-version-api
  name: National Center for Biotechnology Information (NCBI) Version API
  description: '#### Retrieve the current version of all NCBI Datasets services.

    NCBI Datasets services follow the [Semantic Versioning 2.0.0 Schema](https://semver.org/spec/v2.0.0.html).'
  humanURL: https://www.ncbi.nlm.nih.gov/books/NBK25497/
  baseURL: https://eutils.ncbi.nlm.nih.gov/entrez/eutils/
  tags:
  - Version
  properties:
  - type: OpenAPI
    url: openapi/ncbi-version-api-openapi.yml
  - type: Documentation
    url: https://www.ncbi.nlm.nih.gov/datasets/docs/v2/api/rest-api/
  - type: RateLimits
    url: https://kinlane.github.io/ncbi/rate-limits/datasets.yml
  - type: Plans
    url: https://kinlane.github.io/ncbi/plans/datasets.yml
- aid: ncbi:ncbi-virus-api
  name: National Center for Biotechnology Information (NCBI) Virus API
  description: '#### Options to download virus genome data, including the associated sequence and metadata.

    These virus services allow you to get virus genome metadata as a data report or download genome and protein sequence,
    and metadata, as a virus data package, for virus GenBank genomes.'
  humanURL: https://www.ncbi.nlm.nih.gov/books/NBK25497/
  baseURL: https://eutils.ncbi.nlm.nih.gov/entrez/eutils/
  tags:
  - Virus
  properties:
  - type: OpenAPI
    url: openapi/ncbi-virus-api-openapi.yml
  - type: Documentation
    url: https://www.ncbi.nlm.nih.gov/datasets/docs/v2/api/rest-api/
  - type: RateLimits
    url: https://kinlane.github.io/ncbi/rate-limits/datasets.yml
  - type: Plans
    url: https://kinlane.github.io/ncbi/plans/datasets.yml
common:
- type: AgenticAccess
  url: agentic-access/ncbi-agentic-access.yml
- type: DomainSecurity
  url: security/ncbi-domain-security.yml
- type: Authentication
  url: authentication/ncbi-authentication.yml
- type: Authentication
  url: https://www.ncbi.nlm.nih.gov/account/
- type: DeveloperPortal
  url: https://www.ncbi.nlm.nih.gov/home/develop/
- type: TermsOfService
  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