Explore the challenges and strategies for migrating legacy systems to serverless architectures in this 37-minute Devoxx conference talk. Learn about the unique value propositions and potential pitfalls of serverless platforms, including scalability, infrastructure requirements, and hidden costs. Discover design patterns such as the Strangler Pattern and Branch by Abstraction Pattern for safely transitioning applications. Examine serverless-specific concerns like startup time, language considerations, and the shift from monitoring to observability. Gain insights into communicating between serverless functions and on-premises systems, and understand the importance of security in both isolated and collective contexts. By the end of the talk, acquire the knowledge to ask critical questions before designing serverless applications, safely migrate existing systems, and leverage available tools to facilitate the journey.