Late-stage startups have unique needs:
Speed vs quality: Ship fast, but technical debt accumulates. Discuss trade-offs explicitly.
Scaling challenges: Systems built for K users now serving M. Migration and scaling strategies.
Limited resources: Can't throw money at problems like FAANG. Cost-effective solutions matter.
Ownership: You'll own entire systems. Show you can make decisions independently.
Interview style: Often more practical. "How would you solve this problem we actually have?" May discuss their real architecture.
Examples: Stripe, Airbnb, DoorDash. Study their engineering blogs.