Why reactive? How is MicroProfile related to reactive programming? There are many reactive Java libraries but they all work in a different way and provide different API. MicroProfile brings common reactive APIs that can be reused in many libraries to provide a unified experience for many Java developers. Including reactive operators, messaging, REST and more. The core MicroProfile reactive operators API is designed with care by experts behind popular reactive libraries. MicroProfile also provides reactive APIs for asynchronous messaging, REST and thread-control, as well as interceptors to improve the fault-tolerance of your applications. On top of that, MicroProfile aspires to bring unified reactive APIs to Jakarta EE and even to Java SE to make them more accessible to every Java developer. Learning MicroProfile API once will make it easier to get you started with many reactive frameworks with less additional learning.