senior System design
Design a search autocomplete service
Design the typeahead suggestion service for a large product search. Each keystroke must return ranked completions in well under 100ms, with personalization and trending awareness.
Scale targets
Users: 200M DAUQPS: 500k req/secLatency: <50ms p99Storage: ~500GB index
Key areas
Trie / inverted-index structureTop-k ranking + popularity decayPersonalization + history biasIndex updates without downtimeLatency budget per hop