Not all open-access journals are "predatory"! Some very reputable journals do require author's fees for publishing within open-access journals. Here's a short list of qualities that define a "predatory" journal, according to Berger and Cirasella (2015):
- Editors or editorial board members with no or fake academic affiliations
- Lack of clarity about publishing fees
- Publisher names and journal titles with geographic terms that are unrelated to the publisher’s physical location or journal’s geographic scope
- Bogus impact factor claims and invented metrics
- False claims about where the journal is indexed