Reactor Core: This project provides an implementation of Reactive Streams specification. Spring Framework 5.0 provides support for Reactive Programming with the Reactor Core sub-project as a foundation.

Reactor Test: This contains necessary utilities for test verification.

Reactor Extra: On top of Reactor Core, this project provides various operators to work on the data stream to perform required operations.

Reactor IPC: This project provides backpressure furnished and non-blocking inter-process communication support over various network protocols, like HTTP, TCP, UDP, and web sockets. Due to this nature, this module is also helpful when building asynchronous microservice architectures.

Reactor Netty: It is used to provide a reactive feature to Netty, a client server framework to develop network applications.

Reactive Kafka: It is a reactive API for Apache Kakfa-based projects. It is used to communicate with Kakfa in a non-blocking and functional way.

Reactive RabbitMQ: This project is used to equip RabbitMQ (a message broker system) with reactive capabilities.