RSocket Interface in Spring

RSocket in Spring Framework 6 offers a modern network communication protocol for building responsive, resilient, and message-driven applications. It supports bidirectional, multiplexed data streams over a single connection, facilitating efficient communication between microservices or server-client architectures, with enhanced throughput and reduced latency compared to traditional HTTP-based interactions.

1. Introduction

The introduction of RSocket in Spring Framework 6 marks a significant evolution in application communication, offering a protocol that is more efficient and responsive than traditional methods. RSocket facilitates bidirectional, multiplexed data streams over a single connection, making it ideal for microservices and reactive applications where performance and resource utilization are crucial.

Developed with modern distributed systems in mind, RSocket operates over existing application layer protocols like TCP, WebSocket, and Aeron. It leverages a binary protocol, which reduces overhead and enhances protocol efficiency. Its interaction models—fire-and-forget, request-response, request-stream, and channel—cater to a wide range of communication needs, from simple notifications to complex streaming interactions. It offers four interaction models:

  • Fire-and-Forget: The client sends a request without expecting a response.
  • Request-Response: The client sends a request and expects a single response.
  • Request-Stream: The client sends a request and receives a stream of responses.
  • Channel: Both client and server send a stream of messages to each other.

A key feature of RSocket is its support for reactive programming principles, enabling non-blocking back pressure and asynchronous data streams. This alignment with reactive programming makes RSocket a perfect fit for Spring’s WebFlux framework, which is dedicated to building reactive applications.

1.1 Why RSocket in Spring 6?

The integration of RSocket into Spring Framework 6 leverages the strengths of reactive programming, offering developers a powerful tool to build highly scalable and efficient web applications. RSocket’s support for bidirectional communication allows clients and servers to initiate data transfers, pushing updates in real time without the need for polling. This model is particularly beneficial in applications requiring high levels of interactivity, such as live data dashboards, gaming, and messaging apps.

2. Code Example

2.1 Add Dependencies

First, ensure you have Spring Boot 2.2.x or newer, which includes RSocket support. You will need to include the RSocket starter dependency in your pom.xml for both server and client applications:


2.2 Creating an RSocket Server

To create an RSocket server, annotate a controller with @Controller and define message mappings:

public class RSocketServerController {

    // A single request followed by a single response
    Mono requestResponse(String request) {
        return Mono.just("Echo: " + request);

    // Client sends a message without expecting a response
    Mono fireAndForget(String request) {
        System.out.println("Received: " + request);
        return Mono.empty();

    // Client requests a stream of responses
    Flux streamRequest(StreamRequest request) {
        return Flux.interval(Duration.ofSeconds(1))
                   .map(index -> "Data " + index);

    // Both client and server continuously send data to each other
    Flux channel(Flux settings) {
        return settings.map(setting -> "Received: " + setting);

In your application.properties, specify the server port:


2.3 Creating the RSocket Client

To interact with the server, create an RSocket client. You can use Spring’s RSocketRequester for this purpose. Add the same dependencies as the server to your client’s pom.xml. Then, configure an RSocket client in your application by using the RSocketRequester builder provided by Spring Boot to connect to the server and send requests:

public class RSocketClientApplication implements CommandLineRunner {

    private RSocketRequester.Builder rsocketRequesterBuilder;

    public static void main(String[] args) {
        SpringApplication.run(RSocketClientApplication.class, args);

    public void run(String... args) throws Exception {
        RSocketRequester requester = rsocketRequesterBuilder
                .connectTcp("localhost", 7000)

        String routeType = "request.response";

                 .data("Hello, RSocket!")

        // Add other interaction models here

You’re free to experiment with other RSocket Interaction Models.

3. Conclusion

With Spring Boot’s support for RSocket, creating efficient, real-time, bidirectional communication between components is more accessible than ever. By leveraging RSocket’s interaction models, developers can design highly responsive applications that meet modern demands for speed and scalability. Whether building microservices or real-time data streaming applications, RSocket and Spring Boot offer a powerful combination to streamline development and enhance application performance.

For further exploration of RSocket in Spring Boot, consult the official Spring Boot documentation and the Spring Framework RSocket documentation. Happy coding!


An experience full-stack engineer well versed with Core Java, Spring/Springboot, MVC, Security, AOP, Frontend (Angular & React), and cloud technologies (such as AWS, GCP, Jenkins, Docker, K8).
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