Users expect the Explore page to surface trending hashtags almost instantly. We need a fast public endpoint that returns the current top 20 hashtags in under 50 ms without stressing our primary Postgres. The approach is to compute trends from recent posts on a schedule, write the results to Redis (e.g., a sorted set), and have an Express/Node API read only from that cache. Please define the data window for “recent,” the update cadence, tie-breaking rules, cache TTL/expiration, and the endpoint contract, plus how to handle failures if Redis or the job is unavailable. The goal is consistently fast reads and minimal load on the main database.