1 min lesson
Score your own tape
Connect "Spend real time killing your own components" to the decision you would make.
Step 1 of 4
Watch out
Designing only the happy path is the most common way this round goes flat. Cursor's infra exists to survive a region loss and a coordinated abuse spike, so an architecture that never names a failure mode reads as someone who hasn't operated at scale. Spend real time killing your own components.
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Advanced table
Watch the recording with this open and timestamp every red flag
- Dimension
- Quantified
- Pass looks like
- RPS, latency budget and cost ceiling stated up front
- Red flag
- “It should be fast and scalable” with no numbers
- Dimension
- Named tradeoffs
- Pass looks like
- Explicit active-active vs active-passive and an algorithm choice, defended
- Red flag
- One option presented as the only option
- Dimension
- Handled the tail
- Pass looks like
- p99 and a graceful-degradation plan, not just averages
- Red flag
- Designed for the median request only
- Dimension
- Handled abuse
- Pass looks like
- WAF, rate limits and a DDoS/abuse story at the edge
- Red flag
- Assumed all traffic is well-behaved
- Dimension
- Closed on SLOs
- Pass looks like
- SLIs, targets and an error budget that drives decisions
- Red flag
- No measurable definition of done
| Dimension | Pass looks like | Red flag |
|---|---|---|
| Quantified | RPS, latency budget and cost ceiling stated up front | “It should be fast and scalable” with no numbers |
| Named tradeoffs | Explicit active-active vs active-passive and an algorithm choice, defended | One option presented as the only option |
| Handled the tail | p99 and a graceful-degradation plan, not just averages | Designed for the median request only |
| Handled abuse | WAF, rate limits and a DDoS/abuse story at the edge | Assumed all traffic is well-behaved |
| Closed on SLOs | SLIs, targets and an error budget that drives decisions | No measurable definition of done |
Watch the recording with this open and timestamp every red flag.
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Optional practice
Practice: Score your own tape
QDesigning distributed rate limiting for Cursor's edge across regions, what is the core state tradeoff and how do you decide?