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Documenting a Spring REST API Using OpenAPI 3.0


In modern software development, documenting your RESTful APIs is crucial for ensuring clear communication among team members, simplifying integration for consumers, and promoting API adoption. OpenAPI Specification (OAS), formerly known as Swagger Specification, provides a powerful way to describe, document, and consume RESTful APIs.

In this tutorial, we’ll focus on documenting a Spring REST API using OpenAPI 3.0. Spring is a popular framework for building Java applications, and integrating it with OpenAPI will help you generate comprehensive API documentation effortlessly.


  • Basic understanding of Spring Boot framework.
  • Familiarity with RESTful API concepts.
  • Java Development Kit (JDK) installed on your system.
  • Maven or Gradle for dependency management (for this tutorial, we’ll use Maven).
  • An Integrated Development Environment (IDE) such as IntelliJ IDEA or Eclipse.


Step 1: Create a Spring Boot Project

Start by creating a new Spring Boot project. You can use Spring Initializr ( to quickly scaffold your project with the necessary dependencies. For this tutorial, make sure to include Spring Web as a dependency.

Step 2: Add Dependencies

In your pom.xml (if you’re using Maven) or build.gradle (if you’re using Gradle), add the dependencies for integrating OpenAPI with Spring Boot. You will need dependencies for Springdoc OpenAPI.

For Maven:


For Gradle:

implementation 'org.springdoc:springdoc-openapi-ui:1.5.12'

Step 3: Configure OpenAPI

Springdoc OpenAPI library automatically generates OpenAPI documentation for your Spring Boot application. You can configure it through annotations.

In your main application class (usually annotated with @SpringBootApplication), add the @OpenAPIDefinition annotation:

Step 4: Document Your API Endpoints

Document your REST API endpoints using annotations provided by Springdoc OpenAPI library. For example:

Step 5: Access OpenAPI Documentation

Run your Spring Boot application. Once it’s up and running, you can access the OpenAPI documentation by navigating to:


This URL will display the Swagger UI, where you can explore your API documentation interactively.


Documenting your Spring REST API using OpenAPI 3.0 and Springdoc OpenAPI library is a straightforward process. By following the steps outlined in this tutorial, you can generate comprehensive API documentation, making it easier for developers to understand, consume, and integrate with your API.

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