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Reactive Applications with Spring WebFlux Framework

Name: Reactive Applications with Spring WebFlux Framework
Rating: 4.6 (378 reviews)

Creating a Secure, Reactive and non-blocking REST API with Spring WebFlux

Created bySergey Kargopolov

Last updated 6/2026

English

What you'll learn

What Reactive Programming is
Architecture of Reactive Spring Boot application
Create Reactive Spring Boot application
Write and read from a database in reactive/non-blocking way
Use Spring Security in reactive Spring WebFlux application
Implement user authentication in reactive application
Implement JWT authentication in reactive application
Create and validate JSON Web Tokens(JWT)
Use method-level security annotations
Write Spring Security Expressions(SpEL)

Course content

21 sections • 150 lectures • 11h 27m total length

Introduction2:24

Spring Framework and Reactive Streams Specification3:36
Learn how the Spring framework enables reactive non-blocking applications using Spring WebFlux, Project Reactor, and the Mono and Flux types, as defined by the Reactive Streams specification.
Introduction to Reactive programming5:54
Introduction to Data Streams6:36
Back pressure1:34
Data Streams - A quick demo7:19
Reactive Application Overview3:02
Introduction to Spring WebFlux7:42
Quiz: Introduction to Reactive Programming

Java Development Environment & IntelliJ IDEA Ultimate Edition Licence0:29
Creating a new Reactive Spring Boot project8:06
Configure H2 database support in Reactive Spring Boot application6:37
Creating a Database schema4:39
Configure a spring webflux app to create a users table using a schema.sql file and preview it in the H2 web console, with spring.sql.init.mode controlled for embedded H2.
Configuration class to start and stop H2 console web server6:39
Login to H2 database2:40

Introduction to presentation layer2:39
Explore the presentation layer of a reactive spring boot app by building Rest controllers, handling HTTP requests, and converting JSON to Java objects while validating input and ensuring non-blocking responses.
@RestController: Creating and configure the RestController class1:55
@PostMapping: Handle HTTP Post request1:37
Define a Java method to handle http post requests at /users using a post mapping annotation, enabling post requests to localhost:8080/users and preparing to read the request body.
@RequestBody: Reading HTTP Request Body6:39
@Validated: Validating HTTP Request body9:44
Trying if validation works5:46
Mono: Returning a single String value in HTTP Response body3:21
Mono: Returning a User object in HTTP Response body8:12
Learn reactive programming with spring webflux by returning a user rest object in an HTTP response via Mono, using map to expose id, first name, last name, and email.
ResponseEntity: Returning custom HTTP status code8:14
@GetMapping: Handle HTTP GET Request8:15
Flux: Returning multiple objects in HTTP Response body4:06
@RequestParam: Reading URL Query String Parameters4:13
Learn to read url query string parameters for pagination by reading offset and limit with request param annotation, supplying default values, and using these to fetch data in pages.

Introduction to Service layer in Reactive Spring WebFlux application1:39
Build a non-blocking, reactive Spring Boot app by implementing the service layer with core business logic and dependency injection to support create, get, and get all users in the controller.
Creating a Service class3:24
Create a service class in service layer that implements user service interface with create user method accepting a create user request and returning a user rest object, annotated with @Service.
Implementing the createUser() method10:14
Invoke createUser() method from a method in the Rest Controller class3:22
Create User: Trying how it works2:29
Run the app, create a new user via Postman, and verify stored details in the H2 database, noting the need to encrypt passwords in future security work.
Returning Details of a Single User9:32
Get User: Trying how it works3:07

Handling one specific exception with onErrorMap() in Spring WebFlux3:08
Learn to handle exceptions in reactive Spring Boot microservices using the onErrorMap operator, transforming a duplicate key exception into a custom HTTP response with status 409 and the original message.
Handling multiple exceptions with onErrorMap() in Spring WebFlux3:32
Introduction to Global Exception Handling in Spring4:20
@RestControllerAdvice and @ExceptionHandler in reactive application7:05
Trying how Controller Advice works3:56
Formatting Bean validation errors in Spring WebFlux application7:29
Trying how custom bean validation error responses work in Spring WebFlux1:25
Validate custom bean validation error responses in Spring WebFlux by running the app, sending a create user request with short names, and observing concatenated, comma-separated error messages.

Requirements

Basic knowledge of Java
Basic familiarity with Spring Framework

Description

In this video course you will learn how to create Reactive and Non-blocking applications with Spring WebFlux framework.

This course is perfect for beginners and will start with the basics of Spring WebFlux.

You will learn:

- What Reactive programming is and how it is different from an imperative programming style,

- The key differences between the traditional, blocking Spring WebMVC and the non-blocking, Reactive Spring WebFlux applications,

- To create reactive RESTful Web Service application that handles different types of HTTP requests,

- Write and read information from a database in a reactive, non-blocking way.

As you progress through the course, you will learn how to:

- Use Spring Security to protect your Spring WebFlux application,

- Implement user login(authentication),

- Generate and use JSON Web Tokens (JWT) for secure communication

- Validate JWT and read token claims,

- Use method-level security annotations to perform authorization.

You will also learn how to add pagination and read database records in smaller chunks to improve performance.

All important concepts are explained using simple, easy-to-follow slides. The source code is provided, so you can download it and follow along with each lesson.

This course also includes helpful quiz questions to test your knowledge as you go. Plus, there is an active Q&A section where you can get answers to all your questions

By the end of this course, you’ll be able to create fast, secure, and scalable Reactive applications with Spring WebFlux.

Who this course is for:

Java developers interested in learning how to create reactive applications with Spring Framework

Reactive Applications with Spring WebFlux Framework

What you'll learn

Explore related topics

Course content

Introduction1 lecture • 2min

Introduction to traditional(Blocking) Applications3 lectures • 13min

Introduction to Reactive Programming7 lectures • 36min

Creating a Reactive Spring Boot application project6 lectures • 29min

Presentation layer: Accept HTTP request and return HTTP response12 lectures • 1hr 5min

Data layer: Working with a database4 lectures • 15min

Service layer: Business logic7 lectures • 34min

List all users. Pagination in Reactive Spring WebFlux REST application.5 lectures • 19min

Error Handling in Reactive Spring WebFlux applications7 lectures • 31min

Unprotected API endpoints - Security Security in Reactive WebFlux.4 lectures • 12min

Requirements

Description

Who this course is for: