SHOULD always return json objects as top level data structures

The top-level data structure for a request body or response body SHOULD be an object.

Invalid Example

requestBody:
  content:
    application/json:
      schema:
      type: array
      items:
        type: string

Valid Example

requestBody:
  content:
    application/json:
      schema:
      type: object
      properties:
        firstName:
          type: string
        lastName:
          type: string

UKHSA Guidelines API Design

Zalando Guideline 210