Find a free, legal PDF of any paper.

How it works

1. 1

   Paste a title, DOI, or reference

   Whatever you've got — a paper title, a DOI, or the paywalled citation you're stuck on.

2. 2

   We find the source, then a legal free copy

   Corroba resolves the record, then checks Unpaywall and OpenAlex for an open-access version — an author manuscript, a repository copy, arXiv, or an OA publisher.

3. 3

   Read it free — or see where it lives

   Get a direct link to the legal free full text. If there genuinely isn't one, we say so and point you to the publisher.

Questions

How do I find a free PDF of a paywalled paper?

Paste the paper's title or DOI. Corroba looks it up and checks Unpaywall and OpenAlex for a legal open-access copy — often an author's accepted manuscript in a university repository, an arXiv/PubMed Central version, or an open-access publisher copy.

Is this legal? Is it like Sci-Hub?

No — it's the opposite. Corroba only ever links to legal open-access copies that authors, repositories, or publishers have made freely available. It never touches Sci-Hub or any pirated source.

What if there's no free version?

We tell you honestly rather than sending you to a dead or illegal link, and we point you to the publisher's page so you can request it through your library or the author.

Is it free?

Yes — look up papers free, with no sign-up.