Overview of OpenAPI and Swagger

An API description language (or API description format) is a standard format for describing APIs. For example, the snippet below informs the consumers of our API that they need to provide a JSON payload with an email and digest field when calling the POST /login endpoint. In return, they can expect our API to respond with one of the four listed status codes:

paths:
  /login:
    post:
      requestBody:
        description: User Credentials
        required: true
        content:
          application/json:
            schema:
              properties:
                email:
                  type: string
                  format: email
                digest:
                  type: string
                  pattern: ^\\$2[aby]?\\$\\d{1,2}\\$[.\\/A-Za-z0-9]{53}$
      responses:
        '200':
          $ref: '#/components/responses/LoginSuccess'
        '400':
          $ref: '#/components/responses/ErrorBadRequest'
        '401':
          $ref: '#/components...