Unpaywall
3 June 2026
Anyone who regularly reads the scientific literature will be familiar with the experience: you follow a link to a paper, arrive at the publisher's website, and find yourself looking at an abstract and a price. Whether the full text is available depends on your institution's subscriptions. As they cost money, and sometimes a considerable amount, many smaller Universities cut away access quite rigorously, which can be frustrating for researchers and students alike.
Unpaywall is a browser extension that can help locate articles behind paywalls. When you land on a paper's page, it checks automatically whether a legal, freely accessible version exists anywhere. For example, an author's accepted manuscript might be deposited in a university repository, a preprint might be available or an open access version might exist on the publisher's own site. If an available copy exists it will highlight this immediately via a green symbol of an open padlock. If it does not then the symbol is unobtrusively grey and the padlock is closed. If the article exists, then clicking on the green symbol will get straight to the pdf. No further searching, no clicking through to PubMed and back again.
Unpaywall symbol indicating free access to one of our papers
© RudolphLAB, 2026
Why the legal point matters
It is worth being explicit about this: Unpaywall only finds versions that are legally available. It does not route around paywalls by other means. This matters both in principle and in practice – the versions it finds are there because authors or institutions have made them available, often because open access policies require it. Many universities now mandate that published work be deposited in an institutional repository, and for fully open access publications this is a requirement regardless. Unpaywall harvests exactly this kind of legitimate availability.
It is worth mentioning that it is not foolproof. For example, when I tested one of my book chapters that is behind a paywall it gave a green symbol. Clicking on it brought me to the publisher's website, without access to the article. But even if it is not perfect: it does not cost you anything. A quick look at the status via the padlock symbol will potentially bring you one step further than you thought you would get. If it fails not much is lost, but potentially, if the paper is available, time is saved.
What it cannot do
It is not always successful. A paper published before open access was common, in a journal with no open access option, by authors who did not deposit a preprint, will remain behind its paywall. Unpaywall will tell you clearly when it has found nothing. But the hit rate is higher than the manual alternative of checking PubMed, following links to publishers and hoping for the best.
For anyone who reads papers regularly – researchers, students, curious non-specialists without institutional access – it is a quietly useful addition to the browser. Install it once and it simply gets on with things in the background.
You can find it at unpaywall.org.
I came across Unpaywall because Stuart sent me the link. It has already earned a permanent place in my browser.
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