Understanding Outlook add-in permissions

Outlook add-ins specify the required permission level in their manifest. The available levels are Restricted, ReadItem, ReadWriteItem, or ReadWriteMailbox. These levels of permissions are cumulative: Restricted is the lowest level, and each higher level includes the permissions of all the lower levels. ReadWriteMailbox includes all the supported permissions.

You can see the permissions requested by a mail add-in before installing it from AppSource. You can also see the required permissions of installed add-ins in the Exchange Admin Center.

Restricted permission

The Restricted permission is the most basic level of permission. Specify Restricted in the Permissions element in the manifest to request this permission. Outlook assigns this permission to a mail add-in by default if the add-in does not request a specific permission in its manifest.

Can do

  • Get only specific entities (phone number, address, URL) from the item's subject or body.

  • Specify an ItemIs activation rule that requires the current item in a read or compose form to be a specific item type, or ItemHasKnownEntity rule that matches any of a smaller subset of supported well-known entities (phone number, address, URL) in the selected item.

  • Access any properties and methods that do not pertain to specific information about the user or item (see the next section for the list of members that do).

Can't do

ReadItem permission

The ReadItem permission is the next level of permission in the permissions model. Specify ReadItem in the Permissions element in the manifest to request this permission.

Can do

  • Read all the properties of the current item in a read or compose form, for example, item.to in a read form and item.to.getAsync in a compose form.

  • Get a callback token to get item attachments or the full item with Exchange Web Services (EWS) or Outlook REST APIs.

  • Write custom properties set by the add-in on that item.

  • Get all existing well-known entities, not just a subset, from the item's subject or body.

  • Use all the well-known entities in ItemHasKnownEntity rules, or regular expressions in ItemHasRegularExpressionMatch rules. The following example follows schema v1.1. It shows a rule that activates the add-in if one or more of the well-known entities are found in the subject or body of the selected message:

          <Rule xsi:type="RuleCollection" Mode="And">
          <Rule xsi:type="ItemIs" FormType = "Read" ItemType="Message" />
          <Rule xsi:type="RuleCollection" Mode="Or">
              <Rule xsi:type="ItemHasKnownEntity" 
                  EntityType="PhoneNumber" />
              <Rule xsi:type="ItemHasKnownEntity" EntityType="Address" />
              <Rule xsi:type="ItemHasKnownEntity" EntityType="Url" />
              <Rule xsi:type="ItemHasKnownEntity" 
                  EntityType="MeetingSuggestion" />
              <Rule xsi:type="ItemHasKnownEntity" 
                  EntityType="TaskSuggestion" />
              <Rule xsi:type="ItemHasKnownEntity" 
                  EntityType="EmailAddress" />
              <Rule xsi:type="ItemHasKnownEntity" EntityType="Contact" />

Can't do

ReadWriteItem permission

Specify ReadWriteItem in the Permissions element in the manifest to request this permission. Mail add-ins activated in compose forms that use write methods (Message.to.addAsync or Message.to.setAsync) must use at least this level of permission.

Can do

Can't do

  • Use the token provided by mailbox.getCallbackTokenAsync to:

    • Update or delete the current item using the Outlook REST API or access any other items in the user's mailbox.
    • Get the current calendar event item using the Outlook REST API.
  • Use mailbox.makeEWSRequestAsync.

ReadWriteMailbox permission

The ReadWriteMailbox permission is the highest level of permission. Specify ReadWriteMailbox in the Permissions element in the manifest to request this permission.

In addition to what the ReadWriteItem permission supports, the token provided by mailbox.getCallbackTokenAsync provides access to use Exchange Web Services (EWS) operations or Outlook REST APIs to do the following:

  • Read and write all properties of any item in the user's mailbox.
  • Create, read, and write to any folder or item in that mailbox.
  • Send an item from that mailbox

Through mailbox.makeEWSRequestAsync, you can access the following EWS operations:

Attempting to use an unsupported operation will result in an error response.

See also