Open Access Button actually has a search engine where you can enter an article URL, DOI, PMID, Title, Citation, or any other identifying information and it’ll return back a link to the open access version if one is available. Even better, they also have a Google Chrome Browser extension that you can install (also with one click) and which appears in the upper right hand corner of the Chrome Brower ribbon.
Unpaywall harvests open access content from over 50,000 publishers and repositories. Unpaywall is run by Impactstory, a non-profit dedicated to making academic scholarship more accessible and their source code is openly available as well. In fact, Open Access Button actually pulls some of their data from Unpaywall and they are able to do that because Unpaywall is open source. Unpaywall has a browser extension for both Google Chrome and Firefox. So, if you prefer to use Firefox, this tool is the better option.
A drag-and-drop Open Access deposit,
ShareYourPaper.org makes papers Open Access via self-archiving for free. It’s a quick way to increase a research paper’s impact for authors and libraries.

Open access is a broad international movement that seeks to grant free and open online access to academic information, such as publications and data. A publication is defined 'open access' when there are no financial, legal or technical barriers to accessing it - that is to say when anyone can read, download, copy, distribute, print, search for and search within the information, or use it in education or in any other way within the legal agreements. --Open Access.nl
The idea of open access gained standing in the early 2000's. With the internet and world wide web, entry into everything information in the mid 1990's, the dream of open access emerged. Research sharing was a strong component of the early web. The idea of openly, freely sharing shared information materials is a concept that libraries, universities, and researchers recognize; essentially, it is what libraries do face-to-face, provide information resources in a cost effective manner for the communities they serve. Open access encompasses the idea of sharing on a global, internet scale and includes several observable, key characteristics. The three points below identify the viewer perspective of Open Access as based on the
This course helps you to become skilled in Open Access (OA) publishing in the context of Open Science. By the end of the course, you will:
- understand how to publish your work openly and be aware of the advantages
- be able to find an OA publisher for your research
- know how to find a suitable repository to provide - OA and archive your work
- know how to publish OA monographs
- understand funders' expectations and policies on OA
- be able to secure funding for Article Processing Charges (APCs) where applicable
This is a free an online tool that allows you to look up OA policies held by different publishers. If there is discrepancy between what Sherpa Romeo states and the publisher site, also abide by what's stated at the publisher site.