How to specify multiple 404 causes in OpenAPI (Swagger)?

Question

I\'m defining a path for a nested resource (content belonging to a delivery). If the client gets a 404 it could either because the delivery ID was not found, or the deliver

Answer 1

Multiple response types per status code are not allowed in OpenAPI/Swagger 2.0, but are supported in OpenAPI 3.0 by using oneOf.

In OpenAPI 2.0, you can only have a single schema for a 404 response:

      responses:
        '404':
          description: delivery not found, or delivery did not contain any articles
          schema:
            $ref: '#/definitions/Error'

...
definitions:
  Error:
    type: object
    properties:
      status:
        type: integer
      type:
        type: string
      message:
        type: string

where the Error payload can be, say:

{
  "status": 404,
  "type": "DeliveryNotFoundError",
  "message": "delivery not found"
}

{
  "status": 404,
  "type": "NoArticlesInDeliveryError",
  "message": "delivery did not contain any articles"
}