Delivering targeted ads in live sports streaming is not just an adtech challenge – it’s a streaming engineering problem. At JioHotstar, we serve billions of views across live events, handling concurrency spikes that rank among the largest globally. This talk will explore how we built and scaled our custom Server-Guided Ad Insertion (SGAI) system for live sports, where ad breaks are unpredictable in both timing and duration. We’ll discuss why we moved beyond traditional SSAI, and how we engineered: Manifest manipulation and segment stitching on the fly Millisecond-level ad decisioning to insert ads without disrupting playback Strategies for handling massive concurrency surges during peak moments of live matches. We’ll also share real-world lessons from operating at this scale – where streaming architecture and monetisation must work hand-in-hand. Whether you’re building for ads, scale, or live video, this session will provide practical insights into designing systems that balance playback quality with revenue performance. This talk was presented at Demuxed 2025 in London, a conference by and for engineers working in video. Every year we host a conference with lots of great new talks like this – learn more at https://demuxed.com