National Center for Biotechnology Information (NCBI) · Rate Limits

E Utilities

E-utilities rate limits are enforced per IP address. An NCBI API key raises the limit from 3 to 10 requests per second. Higher limits are available upon request. Large automated jobs should run on weekends or between 9 PM and 5 AM ET on weekdays to minimize impact on NCBI servers.

E Utilities is the machine-readable rate-limit profile for National Center for Biotechnology Information (NCBI) on the APIs.io network, in the API Commons Rate Limits shape.

It captures 3 rate-limit definitions.

This profile was written by API Evangelist and has not been verified against a page the provider published; treat every limit as unconfirmed until a dated transcription replaces it.

Tagged areas include Bioinformatics, Genomics, Life Sciences, PubMed, and Sequences.

3 Limits
Method: generated.
Written by API Evangelist and not verified against a page the provider published. Treat every limit as unconfirmed until a dated transcription replaces it.
View Source
BioinformaticsGenomicsLife SciencesPubMedSequencesBLASTTaxonomyChemistryOpen AccessResearch DataOAI-PMH

Work with this as data

Every rate limit here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for rate limits

4 MCP tools reach this
  • find_rate_limitsBrowse and filter every rate limit in the catalog.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools →

Call it yourself

curl for this page
This rate limit 
curl "https://apis.io/api/v1/rate-limits/e-utilities"
All rate limits 
curl "https://apis.io/api/v1/rate-limits?limit=25"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.