Introduction In this article, you learn how detect if your reactive non-blocking Spring app has blocking calls. To achieve this I will use BlockHound BlockHound is a Java agent that works intercepting the blocking calls from JVM classes BlockHound Requirements: Support JDK13+ Use Project Reactor or RxJava2 1. Generate the base code: Go to https://start.spring.io/ Project : Maven Dependendencies: Webflux