| 0-5 min | Clarify functional requirements, constraints, and scope. |
| 5-10 min | Estimate scale, define APIs and core data models. |
| 10-20 min | Build the simplest correct high-level architecture and explain the main data flow. |
| 20-30 min | Deep-dive into the hardest concerns: consistency, transactions, reliability, or scale. |
| 35-45 min | Examine failures, trade-offs, observability, and potential improvements. |
| 5m | 5m | 10m | 15m | 10m |