Demonstrate a Project and Defend Its Design

Choose a work or personal project for a technical demonstration and deep dive. Explain enough of the design and implementation for an interviewer to evaluate your decisions without exposing confidential information. ### Part 1 — Demonstrate the project What did you build, what did you personally own, and how does it work? Describe a significant problem you encountered and explain the project's impact and scale. #### What This Part Should Cover - A concrete user problem and an end-to-end example of the product or feature. - Architecture, implementation boundaries, and individual contributions. - A real difficulty, the response, and evidence of the result. ### Part 2 — Defend a design decision Choose an important implementation or architecture decision. Why did you choose it over an alternative, and what tradeoffs did you accept? #### What This Part Should Cover - The requirements and constraints that made the comparison meaningful. - Costs of the chosen approach and conditions that would favor the alternative. ### Part 3 — Respond to a proposed feature The interviewer asks you to add a new feature whose details are not yet specified. What information do you need before proposing a design, and how would you use the answers to extend your project? #### What This Part Should Cover - User needs, expected behavior, dependencies, and acceptance criteria. - A design connected to the clarified requirements and the existing system. ### What a Strong Answer Covers - Technical depth connected to the demonstrated behavior. - Evidence for impact and scale rather than unsupported claims. - Explicit tradeoffs and a requirements-first response to an incomplete request. ### Follow-up Questions - Which assumption would force the largest change to your current design? - How would you show that the new feature works without weakening an existing permission or data-consistency rule?