openTypeExtension resource type (open extensions)

Namespace: microsoft.graph

Important

APIs under the /beta version in Microsoft Graph are subject to change. Use of these APIs in production applications is not supported. To determine whether an API is available in v1.0, use the Version selector.

Caution

Existing apps that use this feature with baseTask or baseTaskList should be updated, as the to-do API set built on these resources is deprecated as of May 31, 2022. That API set will stop returning data on August 31, 2022. Please use the API set built on todoTask.

Represents open extensions (also known as open type extensions, and formerly known as Office 365 data extensions), an extensibility option that provides an easy way to directly add untyped properties to a resource in Microsoft Graph.

Any open extension added to a resource shows up in the extensions navigation property. Each extension has an extensionName property which is the only pre-defined, writable property for all extensions, along with your custom data. One way to help make sure extension names are unique is to use a reverse domain name system (DNS) format that is dependent on your own domain, for example, com.contoso.ContactInfo. Do not use the Microsoft domain (com.microsoft or com.onmicrosoft) in an extension name.

Derives from the extension abstract type.

Open extensions are supported by the following resources.

Note: * Due to an existing service limitation, delegates cannot create open extension-appended events in shared mailbox calendars. Attempts to do so will result in an ErrorAccessDenied response.

For more information about Microsoft Graph extensibility including limits for open extensions, see Add custom properties to resources using extensions and Add custom data to users using open extensions.

Outlook-specific considerations

Each open extension present on an Outlook resource (event, message, or personal contact) is stored in a MAPI named property. When you create open extensions for Outlook, consider that MAPI named properties are a finite resource in a user's mailbox. When a user's named property quota is exhausted, you can't create any more named properties for that user. This can result in unexpected behavior from clients that rely on named properties to function.

Apply the following guidelines when you create open extensions on Outlook resources:

  • Create the minimum number of extensions required. Most applications should require no more than one extension. Extensions have no set defined properties or structure, so you can store multiple values in a single extension.
  • Avoid naming extensions in a variable manner (such as based on user input, etc.). Each time an open extension is created with a new name that has not been used in a user's mailbox before, a new MAPI named property is created. Removing the extension does not remove the named property.

Use open extensions (for Outlook resources) or extended properties

Open extensions are the recommended solution for most scenarios involving storing and accessing custom data. If, however, you need to access custom data for Outlook MAPI properties that are not already exposed through the Microsoft Graph API metadata, you can use extended properties and its REST API. You can verify which properties the metadata exposes at https://graph.microsoft.com/v1.0/$metadata.

Methods

Method Return Type Description
Create openTypeExtension(in an existing resource instance), or a new baseTask, baseTaskListcontact, event, message, post, todoTask, or todoTaskList that contains an openTypeExtension object. Create an openTypeExtension object in an existing or new resource instance.
Get openTypeExtension Read properties and relationships of openTypeExtension object.
Update openTypeExtension Update openTypeExtension object.
Delete None Delete openTypeExtension object.

Properties

Property Type Description
extensionName String A unique text identifier for an open type data extension. Required.
id String A fully qualified identifier that concatenates the extension type with the extensionName. Read-only.

The id must be defined during the Create operation via one of the following ways:
  • Explicitly define the id property in the request body.
  • Define an extensionName property in the request body, and Microsoft Graph automatically assigns the same value to the id property.
    • In subsequent updates, you can change the extensionName property value to one that's different from the id value.
    • In subsequent updates, specifying only the id property in the request body automatically deletes the extensionName property from the open extension.

Relationships

None

JSON representation

Here is a JSON representation of the resource

{
  "extensionName": "string",
  "id": "String (identifier)"
}