Among the Swagger Tools is Swagger UI, an excellent tool for browsing an OpenAPI specification, the methods defined in the specification, the data models used in the specification. Swagger UI even lets you interact with the service from the documentation. It's a most useful take on "documentation", and to large measure is the whole reason for adopting OpenAPI/Swagger.

Unfortunately implementing the springfox-swagger-ui plugin in a Spring Boot Swagger application gives you a Swagger UI implementatation that's nowhere near as nice/capable as the demo app you see at petstore.swagger.io. There is zero documentation on how to implement the improved Swagger UI via the springfox-swagger-ui plugin. Instead, after quite a bit of experimentation, it seems one must turn to the Swagger UI Docker container.

The Swagger tools, and the OpenAPI format, are an excellent way to document REST API's and even to generate client or server stub libraries to ease implementation. The technology serves two purposes -- a) standardized documentation for REST API's, b) generating code from API documentation in several programming languages. An OpenAPI file is fairly simple to write, you declare REST endpoints, describe the parameters and the request type, and then describe responses. It allows you to define complex object models that can be used either as input to a service, or its output.

Unfortunately the Swagger website doesn't have adequate documentation of using the tools. And it proved difficult to find clear straight-forward tutorials showing how to get started. Even the most powerful tool can be hampered if folks are unable to use it.

The following tutorial is a complete demonstration of, starting from scratch, developing a small Spring Boot service using OpenAPI and the Swagger tools. We show how to go from an OpenAPI spec to generated Spring Boot code, and also how to generate an OpenAPI spec from running Spring Boot code. There are several issues with the workflow of generating code from the OpenAPI spec. It's more effective to instead write the service code, and add in the annotations required for the Swagger tools to generate the OpenAPI spec for you.

With the OpenAPI spec it's easy to produce interactive API documentation that programmers can try out directly in their web browser.

Moving from "cloud-first" to "cloud-only" and therefore "API's" are more important than ever. Concept of the API Economy. Hence necessity for a better method to design REST-ful API's, and help others to use those API's. Another problem is the "Distributed Monolith" which is interlocking dependencies between microservices. Swagger is the solution.

Language agnostic. Helps to generate excellent documentation. No guesswork. Clearly documented REST API's.