Design a news aggregator that pulls from thousands of publishers, classifies topics, and serves personalized and trending feeds

• Assemble feeds at read time to avoid write amplification when millions subscribe to popular topics
• Meet 200ms p95 latency by bounding read work with Redis sorted-set candidate pools
• Scale ingestion across 50,000 publishers with tiered cadences, jitter, and near-minute freshness for top tiers

• Read-time candidate generation
• Tiered publisher cadence
• Partitioned trending counters with dampening