Raffles, voting systems and product launches cause unpredictably high traffic and require highly scalable and robust architectures. Serverless architectures have made it easier building scalable application, but they do not scale limitless automatically. This talk will walk you through limits, core principles, tradeoffs, and best practices for serverless workloads that can meet virtually any demand. We will design a raffle service and show its scalability to over 1 millions users within minutes.