DOI and licence checker

Check any paper.

Paste a DOI, or a link to any paper. You will get the paper itself, whether it is open access, and what its licence lets you do.

Answers come from Unpaywall, which reads them from the publisher and from repositories. Where no licence is recorded, this page says so rather than guessing. Gold, green, hybrid and bronze are set out one at a time on the open access page.