By following similar investigation steps you can also verify the legitimacy of conferences.
If you are unsure of the quality or legitimacy of a conference, begin by verifying if the conference is hosted by well-known organizations, professional, university, or government.
Typically, predatory conferences occur as one-offs, rather than annual events. If there are previous events, browse through the publications and lists of speakers to help you assess the quality. If you recognize any of the speakers do not hesitate to reach out to them and ask them questions directly.
If there is an option to publish your research in any journals associated with the conference, check whether the publication is indexed in any of the databases in your field and review previous articles for quality.