Extending Google Docs with add-ons

Google Docs is a cloud-based document solution with real-time collaboration and powerful tools to compose, edit, and share documents.

You can extend Docs with add-ons that build customized workflow improvements, establish connectivity to third-party systems, and integrate your documents with other Google Workspace applications (like Google Slides).

You can see the Docs add-on others have built on the Google Workspace Marketplace.

What you can do

Here are a few things you can do with an add-on that extends Google Docs:

  • You can read, edit, visualize, and format text in Google Docs using the built-in Apps Script Document service. The service also lets you create and modify tables, images, drawings, and equations appearing in Google Docs.
  • You can create custom menus and define multiple custom dialogs and sidebars interfaces using standard HTML and CSS.
  • You can use add-on triggers to run specified functions when certain triggering events occur.

Docs add-ons are built using Apps Script. To learn more about how to access and manage Google Docs with Apps Script, see Extending Google Docs.

Document structure

The documents created in Google Docs have internal, tree-like structures (similar to HTML or JSON) that define where and how text, images, tables, and other elements appear. The Apps Script Document service defines several classes (such as Paragraph or Table) to help manage the different element types.

See Structure of a document to learn about these element classes and the rules that govern their arrangement.


Apps Script triggers let a script project execute a specified function when certain conditions are met, such as when a document is opened or when an add-on is installed.

See add-on triggers for more information on what triggers can be used with Docs add-ons and what restrictions apply to their use.

Getting started

When you're ready to take a look at some code, check out our add-on samples, including the Docs add-on Quickstart featuring Google Translate.