Does it only include those 35,000 songs in the data set? Or can you use Spotify's similarity features to ID songs outside your set that are similar to sort of "fill out" a playlist? I imagine once you get a few good song "seeds" that match the criteria, you could have Spotify do a bit of the heavy lifting in bringing in other similar songs.

Having trouble connecting since everyone's bombarding the site, but what I got on my first try was very promising. Since this is a natural language thing, it would be amazing to have this work with Siri or Alexa - any plans for something like that? I imagine this would be MUCH better at responding to my kids' music requests than the standard search.