Crossref API: Search 130M+ Research Papers Programmatically (No Key)

Most developers know Google Scholar for finding papers. But Google Scholar has no public API and blocks scraping aggressively. Meanwhile, Crossref quietly maintains a free API with 130 million+ scholarly articles — no API key, no OAuth, no rate limit registration. Just send a GET request and parse JSON. Here is how to use it for research automation, citation analysis, and building academic tools. What Is Crossref? Crossref is the DOI registration agency used by most academic publishers. When a paper gets a DOI (like 10.1038/nature12373), it gets registered in Crossref. Their API exposes metadata for every registered work. 130M+ works. Free. No key. JSON responses. Basic Search import requests def search_papers(query, rows=5): resp = requests.get( "https://api.crossref.org/works", params={ "query": query, "rows": rows, "sort": "relevance" } ) data = resp.json() papers = [] for item in data["message"]["items"]: papers.append({ "title": item.get("title", [""])[0], "doi": item.get("DOI", "