Function-as-a-Service "serverless" cloud offerings provide you with a super easy way to run custom code in response to events. One promise of FaaS model is the ability to scale without limits, up or down, whenever needed. But how does that work in practice? Can AWS Lambda handle thousands of messages per second? How fast can Azure Functions scale up under sudden heavy load? What kind of latency can you expect from Google Cloud Functions? During this session Mikhail will share with you short tales, each of them teaching a lesson about practical scalability of serverless applications. You will also explore the steps to evaluate whether your application profile is suitable for serverless today.