TL;DR — Real-Time Bidding AdTech

Design a real-time bidding (RTB) system for programmatic advertising. When a user visits a webpage, the ad exchange sends bid requests to demand-side platforms (DSPs) which must respond with bids within 100ms. The system must evaluate targeting criteria, compute bid prices using ML models, and serve winning ads — all within stringent latency budgets. Key features: Process bid requests and return bid responses within 100ms. User targeting: audience segments, geo, device, context, retargeting.