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NCBI Entrez E-utilities boundary

NCBI E-utilities documentation boundaries for operations, paging, history writes, request identification and reuse; this review does not verify API execution, clinical validity or permission to redistribute records.

version 1.0.1freshness currentobserved 2026-09-06T19:51:24.542Z

resource.public-data.ncbi-eutilities
sha256:e66593a8d7298d7fb7e6923ea8830238801806f8539c96f462c024c98f2337c1

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Evidence-backed facts

  1. EInfo provides database information; ESearch returns matching UIDs, ESummary returns summaries, EFetch retrieves records, and ELink resolves links. EInfo and ESearch default to XML with optional JSON; EFetch formats depend on the database. informative
  2. The usage guide documents at most 3 requests per second per IP without api_key and a default of 10 with a key. tool must have no spaces; email identifies the software developer, not an end user. Supplying these values alone does not complete their registration. informative
  3. ESearch retstart defaults to 0 and retmax to 20, with a 10,000-record maximum. PubMed and PMC expose only the first 10,000 matches through ESearch. usehistory=y posts results to the History server; WebEnv and query_key bind stored sets. EPost uploads UID sets rather than reading records. informative
  4. The usage guide requires the NCBI Disclaimer and Copyright notice to be visible in software using E-utilities. PubMed abstracts may include protected material; retrieval does not establish redistribution rights. informative