The following terms are used throughout this documentation.
See Publication terminology for additional definitions of terms related to the publication of G Suite add-ons.
Calendar conferencing add-on
A special kind of add-on used to allow third-party developers to present conferencing options in Google Calendar events. These add-ons require a well-developed conferencing solution for the add-on to connect to. Because of this requirement, most developers never have a need to create a Calendar conferencing add-on.
A single "page" of an add-on UI. Cards are composed of different widget objects (buttons, text fields, headers, and so forth), and are defined using the Apps Script built-in Card service.
See Cards for more information.
An add-on whose user interface is defined using the Apps Script built-in
Card service and its associated widget
objects, as opposed to raw HTML and CSS. G Suite add-ons and
Gmail add-ons are card-based.
The current state of the host application. For example, which message currently open in Gmail, which Calendar event you are editing, or which Drive files you have selected are part of the host application's current context. Context, along with other information, is collected into an event object that is passed to the trigger function as a parameter.
The practice of defining triggers that fire when the user enters a specific context, such as when they open an email thread in Gmail. Contextual triggering lets your add-on to provide a UI that is relevant to that context. Contextual triggers are configured in the add-on script project's manifest and thus are a type of manifest trigger.
The original set of add-ons types that only allowed extensions of Google Docs, Sheets, Forms, or Slides. Editor add-ons are not card-based; rather, they required the developer to create a UI from raw HTML and CSS. Each editor add-on can only extend one host application.
See Editor add-ons for more details.
The JSON object that is automatically created when homepages are requested, when the add-on enters contexts it needs to respond to, or as the result of user interactions with widgets in the add-on interface. Once created, event objects are passed to a specified trigger function or callback function. The purpose of event objects is to pass information from the user's client-side environment (such as information they've entered into the add-on interface widgets) to the add-on's server-side code, which then can act on that information and return the appropriate response.
See Event objects for more details.
An add-on that extends Gmail only. Gmail add-ons are card-based. Much of the functionality, behavior, and development details used to create Gmail add-ons is identical to same details used to create G Suite add-ons.
The root UI card of an add-on. Homepages are displayed when users open the add-on, and let your add-on to show content outside of a specific context (for example, when the user is viewing their email threads in Gmail, but hasn't opened one). You define the appearance and behavior of your add-on homepage like any other card.
See Homepages for more information.
Host or Host application
The G Suite application a G Suite add-on extends, such as Gmail or Google Calendar.
A JSON file attached to an Apps Script project. The manifest is used to define project information the script needs to run correctly. For G Suite add-ons, the manifest is used to specify what hosts the add-on can extend and provide certain UI control settings.
A trigger that is defined in a project's manifest, such as a homepage trigger or contextual trigger. Manifest triggers are used exclusively to create and display new cards when an add-on homepage is requested or the add-on enters a context that requires a display update.
Manifest triggers are distinct from other triggers in Apps Script because they aren't built-in (like simple triggers) and can't be be created programmatically with the Apps Script Script service (like installable triggers).
Cards that show content when the user is outside a specific context; for example, when viewing their email threads in Gmail, but hasn't opened a one. Homepages are a kind of non-contextual card.
The section on the right of the host UI where a G Suite add-on's UI appears. Gmail and editor add-ons can also define sidebars.
A condition and automatic event response defined by an Apps Script project or add-on. Triggers fire when their associated event occurs (for example, when an add-on is opened) and cause a specified Apps Script function (the trigger function) to execute automatically. For G Suite add-ons, trigger functions often build new Cards in order to control what part of the add-on UI is displayed. Only certain event types can have triggers.
See Add-on triggers for more information.
An Apps Script function in a project that executes in response to a trigger being fired.
A UI element such as a button, text field, or checkbox. Cards are constructed from a sequence of widget objects, defined by the Apps Script built-in Card service.
See Widgets for more information.
Widget handler function
A function that links a particular widget to a particular action object. Each widget type has a set of defined widget handler functions it can use to connect to actions. Widget hander functions define what kind of user interaction triggers the resulting action, and are a crucial component of widget interactivity.
See Widget handler functions for more information.