Microservices architecture is a new architectural style for creating loosely coupled but autonomous services. Emerging trends in technology-such as DevOps, Platform-as-a-Service (PaaS), containers, and continuous integration and delivery (CI/CD) methods-let organizations create and manage these modular systems on an unprecedented scale that exceeds earlier approaches like service-oriented architecture (SOA). But organizations that refactor monolithic applications into microservices experience widely varying degrees of success. The key to using microservices effectively is a solid understanding of how and why organizations should use microservices to build applications.