Unpaywall is a Firefox extension designed to facilitate access to paywalled scholarly articles. It operates by automatically checking a vast database of over 16 million legal, open-access articles whenever a paywalled article is encountered. If an open version is available, users will see a green tab on the article page, allowing them to access the content for free and legally. This tool enhances the accessibility of scholarly research, making it easier for users to find the information they need without financial barriers.

As an open-source project from Our Research, Unpaywall aims to promote the availability of academic resources. The extension is subscription-based, yet it operates under a nonprofit model, ensuring that the focus remains on increasing access to scholarly work. By simplifying the process of finding open-access articles, Unpaywall is a valuable resource for researchers, students, and anyone interested in academic literature.