I pick five tracks at random as a seed to generate the recommendations (https://spotipy.readthedocs.io/en/2.19.0/#spotipy.client.Spo...). If I want I can also filter recommendations according to certain filters (audio features such as danceability, track duration, etc.).
It uses spotipy (https://github.com/plamere/spotipy) to fetch my liked songs and generate the recommendations.