What is the easiest way to create a Swagger application?

Question

API

You need to create a project similar to petstore in Swagger:
https://petstore.swagger.io/

Answer 1

In any editor. This is a simple yaml or json document.
You can use the same editor https://swagger.io/tools/swagger-editor/
It has a live preview. The spec is also there https://swagger.io/specification/
To display the prepared document, use the SwaggerUI tool https://swagger.io/tools/swagger-ui/
In general, their website has all the information to start using these tools.