Unpaywall – “An open database of 29,928,647 free scholarly articles. We harvest Open Access content from over 50,000 publishers and repositories, and make it easy to find, track, and use.. Get started: research – OA researchers can use Unpaywall to answer research questions about the current and historical state of open access. There are several popular ways to access the data for research: you can use the REST API, the R API wrapper, the Simple Query Tool, or download the whole dataset. A particularly easy way to get started with research is to use Dimensions, Scopus, or Web of Science, which all have Unpaywall data integrated into their databases. That’s the approach used by this recent paper. You might also check out the the canonical reference paper for the dataset, which gives a good overview of the data as a whole. Of course, this is just a very quick overview…if you have any questions, or want to use Unpaywall in a way that’s not described here, please drop us a line and we’ll be happy to help!