Whenever you're ready, walk me through how you'd approach this.
Walk me through a deep dive of your favorite technical project.
Choose a project you know well and explain its architecture, the most important execution path, your individual contribution, and the technical trade-offs behind key decisions. Be prepared to discuss performance, concurrency, failure handling, testing, debugging, and what you would change now. Keep the discussion focused on how the system actually worked rather than only describing its business purpose.