Last September, I wrote how to migrate from an Imperative Programming codebase to a Reactive Programming one in a step-by-step process. Because of its popularity, I illustrated the post with a Spring Boot demo. The final result uses Mono and Flux from Project Reactor. I also made sure that no step in the processing pipeline is blocking thanks to Blockhound. I wrote the code in Java so that it could be accessible to the largest audience. But I’m still a Kotlin fan at heart.