PubMed E-utilities (NCBI)
eutils.ncbi.nlm.nih.gov · Health
Search and fetch biomedical literature from PubMed, PubMed Central, and other NCBI databases. Over 35 million citations. Free, API key optional (higher rate limits with key).
Authentication
API Key authentication
API key optional — get one free at ncbi.nlm.nih.gov/account/. Without a key: 3 req/sec. With a key: 10 req/sec. Pass as &api_key= query param.
Sample Requests
GET
Search PubMed
Search PubMed for articles by keyword. Returns article IDs.
https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?db=pubmed&term=covid-19 vaccine&retmax=5&retmode=json
Hover any highlighted part to learn what it does
curl -X GET "https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?db=pubmed&term=covid-19%20vaccine&retmax=5&retmode=json"
import requests
params = {
"db": "pubmed",
"term": "covid-19 vaccine",
"retmax": "5",
"retmode": "json"
}
response = requests.get(
"https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi",
params=params,
)
print(response.json())const url = new URL('https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi');
url.searchParams.set('db', 'pubmed');
url.searchParams.set('term', 'covid-19 vaccine');
url.searchParams.set('retmax', '5');
url.searchParams.set('retmode', 'json');
const response = await fetch(url);
const data = await response.json();
console.log(data);package main
import (
"fmt"
"io"
"net/http"
"net/url"
)
func main() {
baseURL, _ := url.Parse("https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi")
q := baseURL.Query()
q.Set("db", "pubmed")
q.Set("term", "covid-19 vaccine")
q.Set("retmax", "5")
q.Set("retmode", "json")
baseURL.RawQuery = q.Encode()
targetURL := baseURL.String()
req, _ := http.NewRequest("GET", targetURL, nil)
client := &http.Client{}
resp, _ := client.Do(req)
defer resp.Body.Close()
body, _ := io.ReadAll(resp.Body)
fmt.Println(string(body))
}require "net/http"
require "json"
uri = URI("https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi")
uri.query = URI.encode_www_form({
"db" => "pubmed",
"term" => "covid-19 vaccine",
"retmax" => "5",
"retmode" => "json"
})
http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = uri.scheme == "https"
req = Net::HTTP::Get.new(uri)
res = http.request(req)
puts JSON.parse(res.body)<?php
$url = "https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?" . http_build_query([
"db" => "pubmed",
"term" => "covid-19 vaccine",
"retmax" => "5",
"retmode" => "json"
]);
$opts = ["http" => [
"method" => "GET",
]];
$ctx = stream_context_create($opts);
$res = file_get_contents($url, false, $ctx);
print_r(json_decode($res, true));
GET
Fetch article summary
Fetch title, authors, and journal for a PubMed article ID.
https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esummary.fcgi?db=pubmed&id=34567890&retmode=json
Hover any highlighted part to learn what it does
curl -X GET "https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esummary.fcgi?db=pubmed&id=34567890&retmode=json"
import requests
params = {
"db": "pubmed",
"id": "34567890",
"retmode": "json"
}
response = requests.get(
"https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esummary.fcgi",
params=params,
)
print(response.json())const url = new URL('https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esummary.fcgi');
url.searchParams.set('db', 'pubmed');
url.searchParams.set('id', '34567890');
url.searchParams.set('retmode', 'json');
const response = await fetch(url);
const data = await response.json();
console.log(data);package main
import (
"fmt"
"io"
"net/http"
"net/url"
)
func main() {
baseURL, _ := url.Parse("https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esummary.fcgi")
q := baseURL.Query()
q.Set("db", "pubmed")
q.Set("id", "34567890")
q.Set("retmode", "json")
baseURL.RawQuery = q.Encode()
targetURL := baseURL.String()
req, _ := http.NewRequest("GET", targetURL, nil)
client := &http.Client{}
resp, _ := client.Do(req)
defer resp.Body.Close()
body, _ := io.ReadAll(resp.Body)
fmt.Println(string(body))
}require "net/http"
require "json"
uri = URI("https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esummary.fcgi")
uri.query = URI.encode_www_form({
"db" => "pubmed",
"id" => "34567890",
"retmode" => "json"
})
http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = uri.scheme == "https"
req = Net::HTTP::Get.new(uri)
res = http.request(req)
puts JSON.parse(res.body)<?php
$url = "https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esummary.fcgi?" . http_build_query([
"db" => "pubmed",
"id" => "34567890",
"retmode" => "json"
]);
$opts = ["http" => [
"method" => "GET",
]];
$ctx = stream_context_create($opts);
$res = file_get_contents($url, false, $ctx);
print_r(json_decode($res, true));Postman Setup Guide
- No API key needed to start
- Step 1: Search — GET /esearch.fcgi?db=pubmed&term=your+query&retmax=5&retmode=json
- Step 2: Get details — take IDs from step 1 and call /esummary.fcgi?db=pubmed&id=ID&retmode=json
- Get a free API key at ncbi.nlm.nih.gov/account/ for 10 req/sec
What can you build with PubMed E-utilities (NCBI)?
PubMed E-utilities (NCBI) is a Health API. Developers commonly use health APIs for:
- accessing medical reference data and drug information
- building patient-facing health tracking apps
- integrating with EHR and telemedicine platforms
- looking up ICD codes and clinical terminology
- powering wellness and fitness applications
API Key authentication. You'll receive a key after signing up. Send it with every request — in a header or query parameter. Keep it out of client-side code and never commit it to version control. PubMed E-utilities (NCBI) is free to use, making it a low-risk choice to experiment with.
New to APIs? Read our beginner's guide