Most papers that are free-to-read are available thanks to ‘green Open Access’ copies posted in institutional or subject repositories. The fact that these copies are available for free is fantastic because anyone can read the research, but it does present a major challenge. Is the Digital Object Identifier (DOI) helpful to find the open version of a paper, given there are so many different repositories?
The obvious answer is ‘Google Scholar’. That works great because the resources of Google will probably always be the most comprehensive solution. But Google’s interface requires an extra search step, and its data isn’t open for others to build tools on top of.
The oaDOI is a powerful tool for researchers and librarians alike. If the journal searched for is inaccessible because it has not been subscribed to and it is hidden behind a paywall, oaDOI can supply open copies of each article that has a DOI. That articles may not have a DOI is not as problematic as it may seem since almost all large publishers do provide DOIs for their articles.
An oaDOI is like an alternate Digital Object Identifier (DOI) resolver, with a useful difference: if there’s an Open Access version of the article, the oaDOI URL will send you there. This means that oaDOI will get an article right in PDF, e.g., oadoi.org/10.1038/ng.3260), instead of the paywalled article landing page (e.g., doi.org/10.1038/ng.3260).
Want more info on oaDOI?