How to technically implement the OpenAPI specification? What is Swagger?

OpenAPI specification is a standard for describing REST APIs in JSON or YAML format. Technically, its implementation includes:

• Creating a specification file (for example, openapi.yaml), which describes paths, methods, parameters, data models, and API responses.
• Using tools to generate documentation, server code, or clients based on this specification.

Swagger is a set of tools for working with the OpenAPI specification. It includes:

• Swagger Editor — an online or local editor for creating and editing specifications.
• Swagger UI — a visual interface for interactive API documentation.
• Swagger Codegen — a code generator in various languages based on the specification.

An example of a simple OpenAPI description:

openapi: 3.0.0
info:
  title: Sample API
  version: 1.0.0
paths:
  /users:
    get:
      summary: Get a list of users
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: array
                items:
                  type: string

In Go, libraries like swaggo/swag can be used to generate documentation from code comments.