How Spotify’s Algorithm Knows Exactly What You Want to Listen To

A set of powerful algorithms use your music and your personal details to shape your entire listening experience

Dave Gershgorn
OneZero
Published in
7 min readOct 4, 2019

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Headphones hang upside down as a hand holds a phone with the Spotify logo displayed in front of a screen showing Spotify
Photo: Aytac Unal/Anadolu Agency/Getty

Spotify is doing everything it can to get you to listen to more music.

The company has created algorithms to govern everything from your personal best home screen to curated playlists like Discover Weekly, and continues to experiment with new ways to understand music, and why people listen to one song or genre over another.

While competitors like Apple Music, Amazon Prime Music, and Google Music rely on a mix of paid humans and community-created playlists, Spotify’s main differentiating factor is the level of customization and expansion of music knowledge offered to customers. Spotify needs to continue building out these algorithms because it’s the only way to create custom listening experiences for each of its over 200 million users. As Spotify struggles to grow its business, that differentiating factor needs to be a compelling reason to subscribe to the service.

The home screen of the Spotify app is a prime example of how algorithms govern a listening experience. Its goal is to quickly help users find something they are going to enjoy listening to, according to a presentation by Spotify Research director Mounia Lalmas-Roelleke at the Web Conference earlier this year.

She explained that the home screen is governed by an A.I. system called BaRT (“Bandits for Recommendations as Treatments”). The system’s task is to organize each home screen in a personalized way for each user. That includes the “shelves,” or rows of playlists, that follow a theme like “best of artists” or “keep the vibe going,” and the order the playlists appear on those shelves.

The BaRT system is Spotify’s central balancing act. Its whole purpose is to give you music that Spotify is confident you’ll like, based on your previous listening activity. But Spotify also has to drop in new, fresh music so you don’t get stuck in a loop of listening to the same thing all the time.

The system can be boiled down to two concepts: Exploit and explore. When Spotify exploits, it’s using the information it knows about you, the…

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Dave Gershgorn
OneZero

Senior Writer at OneZero covering surveillance, facial recognition, DIY tech, and artificial intelligence. Previously: Qz, PopSci, and NYTimes.