How does Spotify know what kind of music you’ll like? Whether you have Spotify Premium or not, every Spotify user can find a playlist every Monday called “Discover Weekly.” This playlist is custom-made for the listener with 50 songs that they are likely to enjoy based on a hefty set of data. But what exactly is the Spotify algorithm that outputs this personalized playlist?
The algorithm can be broken down into three main parts in which different pieces of information are collected about songs and users: collaborative filtering, Natural Language Processing, and neural networks that analyze the composition of the song.
Firstly, collaborative filtering, which is simply Spotify finding similar listeners and seeing what they like. This part is fairly straightforward. Spotify finds similar patterns in music choice between you and some other user, typically in playlists that that other user has created with some of the artists you enjoy. But this alone is not enough to give Spotify a full understanding of you or your music choices. For example, popular/trending songs that many people listen to would fill up the Discover Weekly playlist not because it fits a listener’s genre or artist preference, but because it’s catchy and they heard it on the radio.
In order to give Spotify more information about your choice of music, they use something called Natural Language Processing or NLP, which basically labels songs with different tags depending on keywords associated with them on websites and blogs. Once it labels different songs, it can find similarities between songs you like and songs you’ve never listened to by scanning the internet and finding matching keywords.
The third and final pieces of data Spotify collects in its algorithm are the technical elements of the songs you listen to: beats per minute, volume level, time signature, chord progression, types of instruments, etc. The algorithm then scans other songs and finds similarities. This step is crucial in the process because it ensures that songs that many people don’t know or aren’t being discussed on the internet can still be put into these playlists.
If you use Spotify but haven’t listened to your “Discover Weekly” playlist, please do! You might find your all-time favorite song that perfectly aligns with your music taste.