About Research Papers Free
A free search tool that finds the legal, free-to-read copy of a research paper when one exists. No account, no extension, and no papers stored on this site.
What it does
Paste a paper's DOI, a link to it or its title on the home page. The site works out which paper you mean and asks the open-access indexes whether a free copy exists anywhere: in a university repository, on a preprint server such as arXiv, in PubMed Central or on the publisher's own site. If one does, you get a direct link to it, along with a note of which version it is. Every paper has its own page, so you can share the result with other people.
Where the data comes from
Free copies are located with Unpaywall and OpenAlex, two open indexes of the scholarly literature. Paper details and title search come from Crossref and DataCite, the registries that issue DOIs. We are grateful to all four for making their data freely available.
Why the copies are legal
The site links only to copies that an author, a publisher or a repository has made free to read. It does not get around paywalls, log in to anything or use pirate libraries, and it does not host, copy or proxy any paper: every link goes to the site where the paper is legitimately published. Our guide to the kinds of open access explains how these free copies come to exist.
When there is no free copy
Not every paper has one. When the indexes list none, the paper's page says so plainly and offers the legal routes that remain: a ready-written email asking the author for a copy, a Google Scholar search and your library. Our guide to reading research papers for free covers each of them.
How it reads links
If you paste a link that does not contain a DOI, the site may request that page once to read the DOI from its citation tags. It identifies itself as ResearchPapersFreeBot when it does, reads only the page header and stores nothing.