Tutorials 3 min read

A Swagger UI Tutorial for Developers: What Is It and How to Use It?

Swagger UI is an open-source tool for visualizing and interacting with RESTful APIs. In this tutorial, we'll show you Swagger's basic introduction and how to use Swagger UI to Document and Test an API.

A Swagger UI Tutorial for Developers: What Is It and How to Use It?
A Swagger UI Tutorial for Developers: What is it & How to Use it

What is Swagger UI?

Swagger UI is an open-source tool for visualizing and interacting with RESTful APIs (Application Programming Interfaces) that have been documented using the OpenAPI Specification (formerly known as Swagger Specification).


The OpenAPI Specification is a standard format for describing RESTful APIs in a machine-readable format. Swagger UI makes it easy to explore and test these APIs, by providing a user-friendly interface for developers to browse API documentation, test API endpoints, and experiment with different parameters and options.

Swagger UI can be run as a standalone web application, or it can be integrated into existing web applications using a variety of different programming languages and frameworks. It provides a responsive and customizable interface that can be adapted to fit the needs of different teams and projects.

Overall, Swagger UI is a powerful and flexible tool for working with RESTful APIs, and it has become a popular choice among developers and API providers for testing their APIs.

Evolution of Swagger UI

OpenAPI 3.0 was released in July 2017, with major updates and improvements over Swagger 2.0. It provides better security, stricter data type validation, and a more flexible data structure definition, making it a better choice for API specification, particularly for large-scale applications and enterprise-level systems.

How to Use Swagger UI to Document and Test an API?

Swagger UI

Here's an example of using Swagger UI to document and test an API:

  1. Create an OpenAPI specification file in YAML format that describes your API endpoints and operations. For example:
yamlCopy codeopenapi: 3.0.0
  title: Example API
  description: An example API for demonstration purposes
  version: 1.0.0
  - url: http://localhost:8080
      summary: Get a list of users
      description: Retrieves a list of all users
          description: A list of users
                type: array
                  type: object
                      type: integer
                      type: string
                      type: string
                      format: email
  1. Download and add the Swagger UI library to your project. You can download it from the official Swagger UI GitHub repository or use a package manager like npm to install it.
  2. Configure Swagger UI by creating an HTML file that references the Swagger UI library and your OpenAPI specification file. For example:
htmlCopy code<!DOCTYPE html>
  <title>Example API Documentation</title>
  <link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/npm/swagger-ui-dist/swagger-ui.css">
  <script src="https://cdn.jsdelivr.net/npm/swagger-ui-dist/swagger-ui-bundle.js"></script>
    window.onload = function() {
        url: "http://localhost:8080/api-docs",
        dom_id: "#swagger-ui",
        presets: [SwaggerUIBundle.presets.apis],
        layout: "BaseLayout"
  <div id="swagger-ui"></div>

In this example, the Swagger url property in the SwaggerUIBundle configuration object points to the location of your OpenAPI specification file.

Start your API application and open the Swagger UI HTML file in a web browser. You should see a user-friendly interface that displays your API documentation and allows you to test your API endpoints.

By using Swagger UI, you can easily document and test your API, making it more accessible and user-friendly. It's worth mentioning that Swagger Github is a powerful platform that provides developers with a user-friendly interface to create and manage API documentation.

FAQs About Swagger UI

What is the difference between Swagger and Swagger UI?

Swagger and Swagger UI are related but different tools.

Swagger is an API specification, and Swagger UI is a tool for visualizing and interacting with that specification. Swagger UI generates documentation based on the Swagger specification and provides an interactive UI for testing APIs and experimenting with different parameters and options. Using these two tools together can improve API development efficiency.

Is Swagger UI free?

Yes, Swagger UI is free and open-source software released under Apache License 2.0. This means that it can be used, modified, and distributed freely, even for commercial purposes.

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