Understanding Outlook add-in permissions

Outlook add-ins specify the required permission level in their manifest. There are four available levels.

Permission level canonical name	XML manifest name	unified manifest for Microsoft 365 name	Summary description
restricted	Restricted	MailboxItem.Restricted.User	Allows access to properties and methods that don't pertain to specific information about the user or mail item.
read item	ReadItem	MailboxItem.Read.User	In addition to what is allowed in restricted, it allows: regular expressions Outlook add-in API read access getting the item properties and the callback token writing custom properties
read/write item	ReadWriteItem	MailboxItem.ReadWrite.User	In addition to what is allowed in read item, it allows: full Outlook add-in API access except makeEwsRequestAsync setting the item properties
read/write mailbox	ReadWriteMailbox	Mailbox.ReadWrite.User	In addition to what is allowed in read/write item, it allows: creating, reading, writing items and folders sending items calling makeEwsRequestAsync

Permissions are declared in the manifest. The markup varies depending on the type of manifest.

• XML manifest: Use the <Permissions> element.
• Unified manifest for Microsoft 365: Use the "name" property of an object in the "authorization.permissions.resourceSpecific" array.

Note

• There's a supplementary permission needed for add-ins that use the append-on-send feature. With the XML manifest, specify the permission in the ExtendedPermissions element. For details, see Implement append-on-send in your Outlook add-in. With the unified manifest, specify this permission with the name Mailbox.AppendOnSend.User in an additional object in the "authorization.permissions.resourceSpecific" array.
• There's a supplementary permission needed for add-ins that use shared folders. With the XML manifest, specify the permission by setting the SupportsSharedFolders element to true. For details, see Enable shared folders and shared mailbox scenarios in an Outlook add-in. With the unified manifest, specify this permission with the name Mailbox.SharedFolder in an additional object in the "authorization.permissions.resourceSpecific" array.

The four levels of permissions are cumulative: the read/write mailbox permission includes the permissions of read/write item, read item and restricted, read/write item includes read item and restricted, and the read item permission includes restricted.

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. Outlook assigns this permission to a mail add-in by default if the add-in doesn't request a specific permission in its manifest.

Can do

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

• Use the ItemHasAttachment or ItemHasRegularExpressionMatch rule.

• Access the members in the following list that pertain to the information of the user or item. Attempting to access members in this list will return null and result in an error message which states that Outlook requires the mail add-in to have elevated permission.

  • item.addFileAttachmentAsync
  • item.addItemAttachmentAsync
  • item.attachments
  • item.bcc
  • item.body
  • item.cc
  • item.from
  • item.getRegExMatches
  • item.getRegExMatchesByName
  • item.optionalAttendees
  • item.organizer
  • item.removeAttachmentAsync
  • item.requiredAttendees
  • item.sender
  • item.to
  • mailbox.getCallbackTokenAsync
  • mailbox.getUserIdentityTokenAsync
  • mailbox.makeEwsRequestAsync
  • mailbox.userProfile
  • Body and all its child members
  • Location and all its child members
  • Recipients and all its child members
  • Subject and all its child members
  • Time and all its child members

read item permission

The read item permission is the next level of permission in the permissions model.

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.

  Important

  Legacy Exchange user identity tokens and callback tokens will be turned off for all Exchange Online tenants in October 2024 as part of Microsoft’s Secure Future Initiative, which gives organizations the tools needed to respond to the current threat landscape. Exchange user identity tokens will still work for Exchange on-premises. Nested app authentication is the recommended approach for tokens going forward. For more information, see our blog post about nested app authentication and legacy Exchange tokens.

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

• Use regular expressions in a contextual add-in.

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 any of the following APIs.

  • mailbox.makeEwsRequestAsync
  • item.addFileAttachmentAsync
  • item.addItemAttachmentAsync
  • item.bcc.addAsync
  • item.bcc.setAsync
  • item.body.prependAsync
  • item.body.setAsync
  • item.body.setSelectedDataAsync
  • item.cc.addAsync
  • item.cc.setAsync
  • item.end.setAsync
  • item.location.setAsync
  • item.optionalAttendees.addAsync
  • item.optionalAttendees.setAsync
  • item.removeAttachmentAsync
  • item.requiredAttendees.addAsync
  • item.requiredAttendees.setAsync
  • item.start.setAsync
  • item.subject.setAsync
  • item.to.addAsync
  • item.to.setAsync

read/write item permission

Specify read/write item permission 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

• Read and write all item-level properties of the item that is being viewed or composed in Outlook.

• Add or remove attachments of that item.

• Use all other members of the Office JavaScript API that are applicable to mail add-ins, except Mailbox.makeEWSRequestAsync.

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.

read/write mailbox permission

The read/write mailbox permission is the highest level of permission.

In addition to what the read/write item 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.

• CopyItem
• CreateFolder
• CreateItem
• FindConversation
• FindFolder
• FindItem
• GetConversationItems
• GetFolder
• GetItem
• MarkAsJunk
• MoveItem
• SendItem
• UpdateFolder
• UpdateItem

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

Important

Legacy Exchange user identity tokens and callback tokens will be turned off for all Exchange Online tenants in October 2024 as part of Microsoft’s Secure Future Initiative, which gives organizations the tools needed to respond to the current threat landscape. Exchange user identity tokens will still work for Exchange on-premises. Nested app authentication is the recommended approach for tokens going forward. For more information, see our blog post about nested app authentication and legacy Exchange tokens.

See also

• Privacy, permissions, and security for Outlook add-ins