- Danceability (float - between 0.0 and 1.0)
- Energy (float - between 0.0 and 1.0)
- Loudness (float - between -60 and 0 dB)
- Valence (float - between 0.0 and 1.0)
- Valence should be main feature, describes positiveness of track
- Tempo (float - BPM)
- Key (integer - between 0 and 11, 0 = C, moving up semitone)
- mode (integer - 0 for minor, 1 for major, -1 for non-conclusive)