Add-in is a term used, especially by Microsoft, for a software utility or other program that can be added to a primary program.
You can use Office Add-ins to:
Add new functionality to Office clients - For example, augment Word, Excel, PowerPoint, and Outlook by interacting with Office documents and mail items, bringing external data into Office, processing Office documents, exposing third-party functionality into Office clients, and much more.
Create new rich, interactive objects that can be embedded into Office documents - For example, maps, charts, and interactive visualizations that users can add to their own Excel spreadsheets and PowerPoint presentations.
Office Add-ins run across multiple versions of Office including Office for Windows Desktop, Office Online, Office for the Mac, and Office for the iPad.
What can an Office Add-in do?
An Office Add-in can do almost anything a webpage can do inside the browser, such as the following:
- Extend Office native UI by creating custom ribbon buttons and tabs.
- Connect to REST endpoints and web services via HTTP and AJAX.
- Run server-side code or logic, if the page is implemented using a server-side scripting language such as ASP or PHP.
You can create the following types of Office Add-ins:
- Word, Excel, and PowerPoint add-ins that extend functionality
- Excel and PowerPoint add-ins that create new objects
- Outlook add-ins that extend functionality
- A web application that you can host anywhere.
- The add-in manifest that Word uses to discover where your web application is hosted.
Word provides a rich set of APIs that you can use to create add-ins that interact with document content and metadata. Use these APIs to create compelling experiences that integrate with and extend Word. You can import and export content, assemble new documents from different data sources, and integrate with document workflows to create custom document solutions.
You can use any web server technology to host your Word add-in, such as ASP.NET, NodeJS, or Python. Use your favorite client-side framework -- Ember, Backbone, Angular, React -- or stick with VanillaJS to develop your solution and you can use services like Azure to authenticate and host your application.
Word 2013 for Windows
Word 2016 for Windows
Word 2016 for Mac
Word for iOS
We recommend that you adopt the Office design language and use Office UI Fabric to create custom HTML-based experiences in your add-ins. If your organization already has a design language, you're welcome to use it, as long as the end result is a harmonious experience for Office users.
Add-in building blocks
You can use two types of UI elements to create your add-ins:
- Add-in commands enable you to add native UX hooks into Office applications
- Custom HTML-based UI allows you to take advantage of the power of HTML within Office clients.