These are deeper technical rounds that go beyond basic coding. Expect complex data structure and algorithm questions that involve multiple steps or require optimization. Questions often emphasize problem-solving under time constraints, requiring you to walk through your thought process out loud. You might encounter system design questions (especially for higher-level roles) that test your knowledge of designing scalable and efficient systems. For instance, you may be asked to design a system for file storage, message processing, or real-time data streaming.