Design an AI-Powered Search Engine

Design a semantic search engine like Perplexity that understands natural language queries and synthesizes answers from multiple sources.

Functional Requirements

• Natural language query understanding
• Web crawling and indexing
• Multi-source answer synthesis
• Citation and source attribution
• Follow-up questions and refinements
• Real-time information retrieval

Non-Functional Requirements

• Sub-5 second response time
• Index billions of web pages
• Handle 100K+ queries per second
• Fresh index updated within hours
• High relevance and accuracy

Questions to Consider

• How do you combine traditional search with LLM synthesis?
• How do you ensure freshness of information?
• How do you handle queries requiring real-time data?