Podcast home feed
Your task
Design the home-page recommendation system for a podcast app with 100M users and 5M shows (50M episodes). The home feed must mix continue-listening, new-episode alerts from followed shows, and discovery. Constraint: p95 under 200ms for the full feed, the catalog has heavy popularity skew, and episodes go stale fast (a daily news show episode is worthless in 48h).
It covers
- Candidate generation
- Two tower
- Embeddings