Evaluating OA journals for both their quality and relevance for your work can help you avoid predatory publishers!
Journals and publishers that meet important publishing guidelines and industry standards established by the Committee on Publication Ethics (COPE) can be found in several organizations' membership lists and/or directories:
Some publishers ask for fees, or article processing charges (APCs), to make your publication openly accessible. How do authors know when an APC is legitimate or predatory?
Other considerations: How committed is the publisher to Open Access? Is OA their main publishing model, or one of several? What do they do with their revenue?
Check "Which open access journals are reputable?" above for more information.