With Chordify you can play along using a Guitar, Ukulele or Piano.
We have also recently added support for 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.