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SysRound
How it works
Questions
Sample scorecard
Design a URL shortener
100M new links / month
~100 reads per link, p99 < 100 ms
Client
API
Link service
Redis cache
Postgres
POST
GET
hit?
miss
viral link?
hot key!
Shared whiteboard
Alex, your interviewer
Say one link goes viral: a million clicks in an hour on a single code. What breaks first?