There are a few restrictions on what add-ons can do. Improve your users' overall experience by avoiding these pitfalls.
The following restrictions apply to all add-ons. Don't do the following:
Change features in Google Workspace
The Add-ons framework is designed to enhance Google Workspace applications—not to add limits. Consequently, you can't alter existing features or lock down the Google Workspace document sharing model.
Charge users to install
We don't provide a way to charge users for installing add-ons, and add-ons can't include ads. However, you can roll your own payment system or call into an existing billing database. Your add-on can connect to non-Google services that bill users.
Detect many events
Except for certain triggers, add-ons can't tell what a user does outside the add-on itself. For example, you can't detect when the user clicks on the host application toolbar. It is possible to poll for changes in a file's contents from a sidebar's client-side code, although you'll always have a slight delay.
Google Workspace Add-ons
The following restrictions only apply to Google Workspace Add-ons and the use of the Card service. Don't do the following:
Extend all Google Workspace apps
Google Workspace Add-ons can only extend Gmail, Calendar, Drive, Docs, Sheets, and Slides.Eventually Google Workspace add-ons will be able to extend other Google Workspace applications.
Contextual triggering in Drive
Google Workspace Add-ons can only provide contextual triggering for Gmail when reading or composing messages and in Calendar when events are open. Contextual triggering for Drive files is not yet supported. See interim development practices.
Document context in editors
Google Workspace Add-ons don't yet support the use of
document context in editors. That is, you can't use methods such as
to acquire the current document. See
interim development practices.
Use HTML/CSS or client-side scripting
Google Workspace Add-ons must use card-based interfaces. The HTML/CSS interfaces supported by editor add-ons can't be used. Google Workspace Add-ons use a widget-based approach to building user interfaces. This lets the add-on to work well on desktop and mobile platforms without requiring you to build an interface for each.
Full mobile support
For the time being, Google Workspace Add-ons function on desktop web clients. Contextual triggering (that is, Gmail message reading) is also supported from within the Gmail mobile app. Non-contextual homepages are not yet available from the Gmail, Calendar, or Drive mobile apps. Google Workspace Add-ons are not available from mobile web browsers.
Use Apps Script triggers
You can't create or use Apps Script simple triggers in a Google Workspace Add-on.
Use SVG Images
You can't currently use SVG images with Card service cards and widgets.
Have more than 100 widgets
For performance reasons, you can't add more than 100 widgets or 100 card sections to a card.