There are many alternatives to Rapid Evolution for Mac and since it's discontinued a lot of people are looking for a replacement. The best Mac alternative is Mixed in Key. It's not free, so if you're looking for a free alternative, you could try KeyFinder. If that doesn't suit you, our users have ranked nine alternatives to Rapid Evolution and six of them are available for Mac so hopefully you can find a suitable replacement. Other interesting Mac alternatives to Rapid Evolution are Jaikoz (Paid), beaTunes (Paid), SongKong (Paid) and MusicTagger (Paid).
Jaikoz is a tagger that specializes in mass tagging of music file tags. Jaikoz performs acoustic fingerprint matching and metadata lookups automatically using the MusicBrainz, Discogs and Acoustid databases. It can also look up artwork and find duplicates songs.
KeyFinder is an open source key detection tool for DJs who are interested in harmonic and tonal mixing. Designed primarily for electronic and dance music, it is highly configurable and can be applied to many genres.