Start by clarifying requirements and constraints (e.g., scale, multi-tenancy, real-time vs. batch). Then walk through the API endpoints, data model, and concurrency handling for booking conflicts, emphasizing transactional integrity and idempotency. Finally, discuss trade-offs and potential optimizations like caching or event-driven updates.
Pro tip: Highlight how you'd prevent double-booking using database transactions with appropriate isolation levels (e.g., SERIALIZABLE) or optimistic locking, and mention idempotency keys for safe retries. This shows you understand real-world concurrency pitfalls beyond basic CRUD.
Ask about expected scale, user roles (patients, doctors, admins), and whether real-time updates are needed. Define core use cases: search doctors, view availability, book/cancel appointments.
Outline RESTful endpoints: GET /doctors, GET /doctors/{id}/availability, POST /appointments, GET /appointments/{id}, DELETE /appointments/{id}. Include query parameters for filtering by specialty, date, etc.
Propose entities: Doctor, Patient, Appointment, and Availability/Schedule. Specify key fields, relationships, and indexes (e.g., unique constraint on doctor_id + start_time to prevent overlaps).
Explain how to compute available slots from doctor schedules and existing appointments. For booking, use transactions with row-level locking or optimistic concurrency to avoid double-booking, and return 409 Conflict on failure.
Address caching availability, handling high read loads, and ensuring idempotency for booking requests. Mention monitoring, logging, and potential use of message queues for notifications.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
Came right after the design question, which was a bit of a gear shift.
Select a project that showcases both technical depth and your ability to navigate ambiguity, then narrate it using a clear structure: context, problem, your specific actions, technical trade-offs, and measurable outcomes. Keep the story focused on your individual contributions and the decisions you made, not just the team's work.
Pro tip: Quantify the impact of your technical decisions (e.g., latency reduction, cost savings) and explicitly connect trade-offs to business or user value—this shows you think like an engineer who understands the product, not just the code.
Briefly describe the project's purpose, your role, the team size, and the business goal. Keep it to 2-3 sentences so the interviewer understands the stakes.
Explain the specific challenge you faced, including any unclear requirements, technical unknowns, or constraints. Highlight why it was non-trivial.
Walk through the steps you took, focusing on your individual contributions. Describe the alternatives you considered and why you chose your approach.
Explain the trade-offs you made (e.g., performance vs. maintainability, speed vs. scalability) and how you adapted when things changed or new information emerged.
Quantify the outcome (e.g., reduced latency by 30%, saved $X in costs) and reflect on what you learned or would do differently next time.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.