> ## Documentation Index
> Fetch the complete documentation index at: https://www.mintlify.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Complex data types

> Describe APIs with flexible schemas using oneOf, anyOf, and allOf keywords for optional properties, polymorphism, and multiple data formats.

When your API accepts multiple data formats, has conditional fields, or uses inheritance patterns, OpenAPI's schema composition keywords help you document these flexible structures. Using `oneOf`, `anyOf`, and `allOf`, you can describe APIs that handle different input types or combine multiple schemas into comprehensive data models.

## `oneOf`, `anyOf`, `allOf` keywords

For complex data types, OpenAPI provides keywords for combining schemas:

* `allOf`: Combines multiple schemas (like merging objects or extending a base schema). Functions like an `and` operator.
* `anyOf`: Accepts data matching any of the provided schemas. Functions like an `or` operator.
* `oneOf`: Accepts data matching exactly one of the provided schemas. Functions like an `exclusive-or` operator.

<Warning>Mintlify treats `oneOf` and `anyOf` identically since the practical difference rarely affects using the API.</Warning>

For detailed specifications of these keywords see the [OpenAPI documentation](https://swagger.io/docs/specification/data-models/oneof-anyof-allof-not/).

<Info>The `not` keyword is currently unsupported.</Info>

### Combining schemas with `allOf`

When you use `allOf`, Mintlify performs some preprocessing on your OpenAPI document to display complex combinations in a readable way. For example, when you combine two object schemas with `allOf`, Mintlify combines the properties of both into a single object. This becomes especially useful when leveraging OpenAPI's reusable [components](https://swagger.io/docs/specification/components/).

```yaml theme={null}
org_with_users:
  allOf:
    - $ref: '#/components/schemas/Org'
    - type: object
      properties:
        users:
          type: array
          description: An array containing all users in the organization
# ...
components:
  schemas:
    Org:
      type: object
      properties:
        id:
          type: string
          description: The ID of the organization
```

<ParamField body="org_with_users" type="object">
  <Expandable>
    <ParamField body="id" type="string">
      The ID of the organization
    </ParamField>

    <ParamField body="users" type="object[]">
      An array containing all users in the organization
    </ParamField>
  </Expandable>
</ParamField>

### Providing options with `oneOf` and `anyOf`

When you use `oneOf` or `anyOf`, the options display in a tabbed container. Specify a `title` field in each subschema to give your options names. For example, here's how you might display two different types of delivery addresses:

```yaml theme={null}
delivery_address:
  oneOf:
    - title: StreetAddress
      type: object
      properties:
        address_line_1:
          type: string
          description: The street address of the recipient
        # ...
    - title: POBox
      type: object
      properties:
        box_number:
          type: string
          description: The number of the PO Box
        # ...
```

<ParamField body="delivery_address" type="object">
  <div className="mt-4 rounded-xl border border-gray-100 px-4 pb-4 pt-2 dark:border-white/10">
    <Tabs>
      <Tab title="StreetAddress">
        <ParamField body="address_line_1" type="string">
          The street address of the residence
        </ParamField>
      </Tab>

      <Tab title="POBox">
        <ParamField body="box_number" type="string">
          The number of the PO Box
        </ParamField>
      </Tab>
    </Tabs>
  </div>
</ParamField>


## Related topics

- [Workflows overview](/docs/workflows/index.md)
- [Files](/docs/create/files.md)
- [Navigation](/docs/organize/navigation.md)