Reel Friends: Building Social Discovery at Billion-User Scale

Friend Bubbles is a feature that shows Reels your friends have watched and reacted to, and while it appears simple on the surface, the actual implementation required deep engineering.

On the Meta Tech Podcast, Pascal Hartig met with Reels team engineers Subasree and Joseph to talk about how they built out this feature. The conversation centered on the evolution of the machine learning model, the differences in iOS and Android user behavior, and the unexpected discovery that solved the final piece of the puzzle.

The episode is available on Spotify, Apple Podcasts, and Pocket Casts, as part of a podcast format Meta uses to showcase work across its engineering organization.