System Design Interview
Retrieval-augmented Q&A over company documents inspired by Perplexity, Notion AI and Glean: documents split into overlapping passages and embedded by workers, hybrid vector and keyword retrieval, cross-encoder re-ranking, answers grounded in cited passages, an answer cache keyed by meaning and document version, and access lists enforced inside retrieval. A teaching design.
Build this system yourself on the canvas below. Add components, connect them, and run traffic simulations to see where your design holds up and where it breaks.
You're in the middle of an interview session. Leaving now will end your current attempt.
Explore concept overviews, real-system examples, key tradeoffs, and interview talking points for each roadmap section.
You've conquered this phase. These are the skills you now own:
