OpenAPI extension: x-additionalPropertiesName

OpenAPI allows description of "additionalProperties" that may be included in a schema. Their names are unknown, but the field types can be added to the API description so that producers and consumers understand whether additional fields are permitted and any additional rules that apply.

Since the field names are not specified, they are displayed with a generic name in the API reference documentation. Use x-additionalProperties to display a more meaningful name in this scenario.

Location

Use x-additionalPropertiesName as a property of additionaProperties in an OpenAPI Schema.

Options

Examples

The following example shows a schema that accepts any fields as long as the values are numbers between 0-100, for a set of sensors reporting fill levels:

components:
  schemas:
    FillLevel:
      type: object
      properties:
        reportTime:
          type: string
          format: date-time
          description: Report creation time.
      required:
        - reportTime
      additionalProperties:
        x-additionalPropertiesName: percentage
        type: integer
        minimum: 0
        maximum: 100

The additional properties appear in the documentation as percentage*.

Resources

• Control which extensions are included in your API reference documentation with the showExtensions configuration setting.
• See all theme.openapi configuration settings.
• See a full list of supported OpenAPI extensions.