With Chordify you can play along using a Guitar, Ukulele, Piano or Mandolin.
Currently Mandolin is only available on the Chordify website and the Android app though, not yet the iOS app.
Please note: At Chordify we're currently mainly focused on extracting chord data from songs—our algorithm is not at a point where it can reliably transcribe individual melody lines. This means we only serve chords – or one hand for piano players.