NCBI E-Utilities

The Entrez Programming Utilities (E-utilities) are a set of eight server-side programs that provide a stable interface into the Entrez query and database system at the National Center for Biotechnology Information (NCBI). The E-utilities use a fixed URL syntax that translates a standard set of input parameters into the values necessary for various NCBI software components to search for and retrieve the requested data. The E-utilities are therefore the structured interface to the Entrez system, which currently includes 38 databases covering a variety of biomedical data, including nucleotide and protein sequences, gene records, three-dimensional molecular structures, and the biomedical literature, e.g., PubMed.

Associated Institutions

U.S. National Library of Medicine
National Center for Biotechnology Information (NCBI)

Application Domains
  • Biology
  • Clinical
  • Genomics
  • Literature
  • Metabolomics
  • Proteomics
Other Resource Type
Software Subtype
  • Bioinformatics
  • Computational biology tools
  • Gene expression
  • Genome analysis
  • Nucleotide sequence analysis
  • Protein sequence analysis
  • Structures
Programming Languages
Operating Systems
Included Components
Dataset Subtype
  • Human annotated
  • Machine annotated
  • Structured data
Data Model Subtype
Online Resource Subtype
Knowledge Base Subtype
Intended User Types
  • Clinician
  • Clinical researcher
  • Informatics researcher
  • Software developer
Available Documentation
  • API
  • PDF documentation
  • Web page/HTML documentation