Explore the concept of modern modular monoliths in this 53-minute conference talk from Spring I/O 2024 in Barcelona. Delve into the evolution of monolithic architectures and learn why decomposing monoliths into microservices isn't always necessary. Discover how Spring Modulith applies lessons from microservices to create a new paradigm for modern monoliths. Understand the differences between modern modular monoliths and traditional monolithic structures, and identify the challenges they aim to resolve. Gain insights into when and how to apply modular architecture principles to Spring Boot applications using Spring Modulith. By the end of this talk, acquire the knowledge to make informed decisions about monolithic versus microservices architectures and leverage Spring Modulith for creating well-organized, maintainable monolithic applications.