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The Outlook add-in API subset of the Office JavaScript API includes objects, methods, properties, and events that you can use in an Outlook add-in.
Preview APIs are subject to change and aren't intended for use in a production environment. We recommend that you try them out in test and development environments only. Don't use preview APIs in a production environment or within business-critical documents.
To use preview APIs:
You must use the preview version of the Office JavaScript API library from the Office.js content delivery network (CDN). The type definition file for TypeScript compilation and IntelliSense is found at the CDN and DefinitelyTyped. You can install these types with npm install --save-dev @types/office-js-preview (be sure to remove the types for @types/office-js if you've previously installed them).
You may need to join the Microsoft 365 Insider program for access to more recent Office builds in Outlook on Windows and on Mac.
You may need to configure the Targeted release option on your Microsoft 365 tenant to preview features in Outlook on the web. For more information, see the "Targeted release" section of Set up the Standard or Targeted release options.
The preview requirement set includes all of the features of requirement set 1.14.
Important
This documentation is for a preview requirement set. This requirement set isn't fully implemented yet, and clients won't accurately report support for it. You shouldn't specify this requirement set in your add-in manifest.
The following features are in preview.
Added events to activate an event-based add-in on a message in read mode when it contains certain attachment types or custom internet headers.
Available in: Classic Outlook on Windows (Microsoft 365 subscription)
Added an attribute to the <LaunchEvent> XML element to specify the internet header name on which the OnMessageReadWithCustomHeader event occurs.
Available in: Classic Outlook on Windows (Microsoft 365 subscription)
Added an XML element to specify the file extension of the attachment included in a message on which the OnMessageReadWithCustomAttachment event occurs.
Available in: Classic Outlook on Windows (Microsoft 365 subscription)
Added a new object that represents the all-day event property of an appointment in compose mode.
Available in: Classic Outlook on Windows (Microsoft 365 subscription)
Added a new property that represents if an appointment is an all-day event.
Available in: Classic Outlook on Windows (Microsoft 365 subscription)
Added a new method to get additional properties and run operations on selected messages.
Available in: Classic Outlook on Windows (Microsoft 365 subscription)
Added a new object that represents the properties and methods of a selected message in compose mode.
Available in: Classic Outlook on Windows (Microsoft 365 subscription)
Added a new object that represents the properties and methods of a selected message in read mode.
Available in: Classic Outlook on Windows (Microsoft 365 subscription)
Added an event.completed option to format a message in a Smart Alerts dialog using Markdown. To learn more, see the Smart Alerts walkthrough and Limitations to formatting the dialog message using Markdown.
Available in: Classic Outlook on Windows (Microsoft 365 subscription)
Added the NeverShowAgainOption element as a child of the <PreProcessingDialog> element. This element adds a "Don't show me this message again" checkbox to the preprocessing dialog to prevent it from appearing again.
Available in: Outlook on the web and on Windows (new and classic) (Microsoft 365 subscription)
Added the inputType attribute to the ReportingOptions element. This attribute uses radio buttons for the reporting options of a preprocessing dialog.
Available in: Outlook on the web and on Windows (new and classic) (Microsoft 365 subscription)
Added the commandId and contextData options to the event.completed call. These options configure a task pane to open after a user selects Report from the preprocessing dialog.
Available in: Outlook on the web and on Windows (new and classic) (Microsoft 365 subscription)
Added a property that gets an object to temporarily set the content displayed in the body or subject of a message in read mode.
Available in: Classic Outlook on Windows (Microsoft 365 subscription)
Added an object that provides properties to temporarily set the content displayed in the body or subject of a message in read mode.
Available in: Classic Outlook on Windows (Microsoft 365 subscription)
Added an object that provides a method to temporarily set the content displayed in the body of a message in read mode.
Available in: Classic Outlook on Windows (Microsoft 365 subscription)
Added an object that provides a method to temporarily set the content displayed in the subject of a message in read mode.
Available in: Classic Outlook on Windows (Microsoft 365 subscription)
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Training
Module
Build Office Add-ins for Outlook - Training
This module walks through development of Office Add-ins for Microsoft Outlook.
Certification
Microsoft Office Specialist: Outlook Associate (Office 2019) - Certifications
Demonstrate that you have the skills needed to get the most out of Outlook 2019 by earning the Microsoft Office Specialist (MOS) certification.
Documentation
Outlook JavaScript API requirement sets - Office Add-ins
Learn more about the Outlook JavaScript API requirement sets.
Outlook add-in API requirement set 1.8 - Office Add-ins
Requirement set 1.8 for Outlook add-in API.
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