Drive Discovery with a Requirements Checklist and Assumptions
Requirements discovery for a system design interview turns a vague prompt into confirmed requirements, stated assumptions, and priorities before any architecture is drawn. This hands-on lesson applies a seven-part checklist to a flash-sale storefront prompt. Covers: Users and client types, regions, peak versus average load, latency and data sensitivity, availability, budget, a one-page requirements and assumptions note, and a bounded workload summary. Practice: How would you turn a vague prompt into assumptions? Prerequisites: Basic cloud components such as caches, databases, and load balancers.
A system design round scores requirement clarity and decision quality, not recall of cloud services. An interviewer says, “Design a seasonal online storefront for flash-sale peaks.” Before proposing an architecture, let’s turn that prompt into constraints we can defend.
Answering with a cache, database, or load balancer too quickly locks the design into untested assumptions. For the seasonal storefront, the same browse-catalog, add-to-cart, and checkout flow changes substantially if shoppers arrive from one region or several, catalog data can be briefly stale, or checkout must remain correct during a peak.
Use the discovery checklist to expose architecture boundaries
Let’s ask about users and client types first. Are the primary users browser shoppers, mobile-app shoppers, internal catalog editors, or partner integrations? Each group changes authentication, traffic shape, and the interfaces the design must support.
Next, establish geography and regions. A single-market storefront can accept different network paths and recovery choices than a storefront serving ...