I have a bunch of DOIs, now I would like to fetch the corresponding PDF and the title and authors, creation/publish date, keywords, abstract if possible, etc. I understand that many articles are behind a paywall so don't expect to get the PDFs for those. But I would still like to get the other metadata for those articles, even though they are behind the paywall (since I imagine that info is public).

To summarize, looking for some/all of these properties in preferably JSON or XML form (except the PDF, in PDF form, if freely available):

  • title
  • authors
  • journal
  • publicationDate
  • keywords
  • abstract/description

I tried looking here at the DOI API but it only seems to provide this:

  "responseCode": 1,
  "handle": "10.1000/1",
  "values": [
      "index": 100,
      "type": "HS_ADMIN",
      "data": {
        "format": "admin",
        "value": {
          "handle": "0.NA/10.1000",
          "index": 200,
          "permissions": "011111111111"
      "ttl": 86400,
      "timestamp": "2000-04-13T15:08:57Z"
      "index": 1,
      "type": "URL",
      "data": { "format": "string", "value": "http://www.doi.org/index.html" },
      "ttl": 86400,
      "timestamp": "2004-09-10T19:49:59Z"

I saw CORE, which might have the metadata, but it isn't public domain / free / open source for commercial use, which I would like. Also checked at the Elsevier APIs (Mendeley and Scopus), but they are not free for commercial use either.

  • I suspect the CrossRef REST API might work for you, at least for the metadata/citation info.
    – anjama
    May 15, 2019 at 12:23
  • Darnit their license is restrictive too! Hoping for PUBLIC DOMAIN. May 15, 2019 at 16:20
  • Arxiv looks like it might be close to that, but they don't have every article. May 15, 2019 at 16:22
  • Pubmed has 29 million. Looking here. May 15, 2019 at 16:34
  • Here it is. It is using SciHub. May 15, 2019 at 20:59

1 Answer 1


the Crossref REST API is public and doesn't have a license - all our metadata are available for reuse without restriction. That's because we believe that metadata are facts and facts cannot be owned or licensed. (The license CC 4 refers only to the documentation on how to use the API :-))

We have 105 million DOIs about 25% of those have full-text links that go to HTML or PDFs. I'm not sure of the exact queries you'll need but if you end up using it and need help you can open tickets there on GitHub.

  • Can you elaborate on what the license means in relation to the API por favor? My read was that if you download it through the API then you can't use it for commercial purposes. May 15, 2019 at 21:27
  • 1
    Hi - the metadata license statement I linked to as "doesn't have a license" states we don't claim any ownership over the metadata. There is nothing that says you can't use it for commercial purposes. In fact, it says "Individual items of bibliographic metadata and associated DOIs may be cached and incorporated into the user's content and systems." Unless you read something somewhere else? In which case I will correct it!
    – ynnig
    May 17, 2019 at 14:36
  • How come api.unpaywall.org/v2/10.1002/… works, but api.crossref.org/works/10.1002/… breaks? Do you guys have a way of getting that doi? May 18, 2019 at 5:24
  • 1
    No idea @LokasaMawati but will ask my support manager!
    – ynnig
    May 26, 2019 at 10:57

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