How Spotify Wrapped Scales for 7M Users

Spotify Wrapped turns listening history into a personalized year-end summary. The design challenge has two distinct workloads: preparing summaries from historical events and serving those summaries when many users open them at launch.

This lesson uses documented Spotify engineering reports for historical examples and an explicitly hypothetical architecture for design practice. The title’s seven-million figure is not established here as Spotify’s measured audience or concurrency. Later, we use seven million launch requests as a sample capacity exercise.

Establish the scale and the measurement

Spotify reported 602 million monthly active users for Q4 2023 and more than 225 million users engaging with that year’s Wrapped campaign. These are different populations, and neither is a concurrent-request count. Spotify’s Q4 2023 report.