Machine Learning System Design Interview, issue 10, Nov 28, 2025
The SOTA Trap
Senior ML Engineer interview at LinkedIn, and the interviewer asks:
“We have 500 million users in a social graph. We need a real-time model to recommend new connections. Design the architecture.”
The trap almost every ML engineer falls into when designing LinkedIn-scale recommendation systems.
The full answer, with the mechanism and the arithmetic, is for paid subscribers on Substack.