50-minute mock

1. → contract + scope5 min

   • users, critical read/write path, out of scope
   • scale estimate with an explicit peak factor
   • SLOs written down and visible

2. skeleton design8 min

   • boxes own something; arrows carry named requests
   • stateful boundaries marked
   • one bottleneck named before scaling mechanisms

3. APIs + data model7 min

   • core endpoints with shapes
   • partition key and access patterns
   • consistency choice stated with a reason

4. hardest path deep dive12 min

   • the one path that decides seniority, fully traced
   • numbers attached to every mechanism
   • alternative considered and rejected on record

5. failure + security + ops8 min

   • top failure and its retry semantics
   • tenant/abuse boundary drawn
   • what pages, what dashboards, how it rolls out

6. recap + risks10 min

   • top three risks named explicitly
   • cost and degradation posture stated
   • reversal triggers: what would change the design

self-scorecard · 1–4 per axis