NCBI Entrez E-utilities
FreeLiveLast verified 29 Sept 2026
Search and fetch records from PubMed, GenBank, Gene, Protein and other NCBI databases by query or ID.
Example request
curl -s 'https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?db=pubmed&term=asthma&retmode=json'
Free tier, in plain English
Free without a key at up to 3 requests a second; a free NCBI account key raises that to 10. Large jobs should run at night or weekends US Eastern time.
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