You have 35 minutes to design a fictional neighborhood delivery service. Start by finding out what it must do and which failures matter. A box diagram without those constraints can't show whether the design is suitable. Use the first few minutes to agree on scope, then estimate the workload that drives a design decision. Describe the API and data before adding specialized infrastructure.
An interviewer can follow your reasoning when you connect each decision to a requirement. Explain the trade-off and test a failure: what happens when the database is slow or a request is retried? There is no universal scorecard or mandatory list of components. In these exercises, you practice scope, scale, request flow and failure analysis. All workloads in this course are fictional inputs for calculation.