Crossref

api.crossref.org · Science

Science No Auth Free & Open Academic Research DOI

Official DOI registration agency for scholarly content. Query metadata for over 145 million DOIs including articles, books, datasets, and conference papers. Free, no API key required.

Authentication

No authentication requiredFree to use with no key needed.

Sample Requests

GET Look up a DOI

Get full metadata for a DOI.

https://api.crossref.org/works/10.1038/nature12373

Hover any highlighted part to learn what it does

curl -X GET "https://api.crossref.org/works/10.1038/nature12373"

import requests
response = requests.get(
    "https://api.crossref.org/works/10.1038/nature12373",
)
print(response.json())

const url = 'https://api.crossref.org/works/10.1038/nature12373';

const response = await fetch(url); 
const data = await response.json();
console.log(data);

package main

import (
	"fmt"
	"io"
	"net/http"
)

func main() {
	targetURL := "https://api.crossref.org/works/10.1038/nature12373"
	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://api.crossref.org/works/10.1038/nature12373")

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://api.crossref.org/works/10.1038/nature12373";
$opts = ["http" => [
    "method" => "GET",
]];
$ctx = stream_context_create($opts);
$res = file_get_contents($url, false, $ctx);
print_r(json_decode($res, true));

GET Search works

Search across all registered DOI metadata.

https://api.crossref.org/works?rows=5&query=climate change

Hover any highlighted part to learn what it does

curl -X GET "https://api.crossref.org/works?rows=5&query=climate%20change"

import requests
params = {
    "rows": "5",
    "query": "climate change"
}
response = requests.get(
    "https://api.crossref.org/works",
    params=params,
)
print(response.json())

const url = new URL('https://api.crossref.org/works');
url.searchParams.set('rows', '5');
url.searchParams.set('query', 'climate change');

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://api.crossref.org/works")
	q := baseURL.Query()
	q.Set("rows", "5")
	q.Set("query", "climate change")
	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://api.crossref.org/works")
uri.query = URI.encode_www_form({
  "rows" => "5",
  "query" => "climate change"
})

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://api.crossref.org/works?" . http_build_query([
    "rows" => "5",
    "query" => "climate change"
]);
$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

Get Postman ↗

No API key needed
Try GET https://api.crossref.org/works?query=deep+learning&rows=5
Add &[email protected] for polite pool access
Use /works/{doi} to fetch a specific paper by DOI

What can you build with Crossref?

Crossref is a Science API. Developers commonly use science APIs for:

accessing research datasets and scientific literature
powering academic and R&D applications
running scientific calculations and simulations
visualising experimental and observational data
integrating with research and reference databases

No authentication required. This API is open — no signup or key needed. Ideal for quick prototypes and public-facing features. Crossref is free to use, making it a low-risk choice to experiment with.

New to APIs? Read our beginner's guide

Open documentation ↗