Users must install and authorize an add-on before they
can open and use it. Because these steps are the first part of the
add-on user experience, understand them before you
start creating your own add-ons.

Learn how users can install, authorize, and start using add-ons.

## Install add-ons

Install an add-on to make it available in the
Google Workspace [host
application](https://developers.google.com/workspace/add-ons/guides/glossary#host_or_host_application) it
extends.

Install published add-ons from the Google Workspace host
application or from the
[Google Workspace Marketplace](https://workspace.google.com/marketplace).
Domain administrators can also install add-ons on behalf of their
users from the Google Workspace Marketplace. You can also [install unpublished
add-ons](https://developers.google.com/workspace/add-ons/how-tos/testing-workspace-addons)
you're developing so that you can test them. Authorize an installed
add-on the first time you use it.

See [Publish
add-ons](https://developers.google.com/workspace/add-ons/how-tos/publish-add-on-overview).

## Authorize add-ons

After you install an add-on, it's available in the
Google Workspace [host
application](https://developers.google.com/workspace/add-ons/guides/glossary#host_or_host_application) it
extends. When a user first uses the add-on, the host
application presents an authorization card or dialog. This card explains what
the add-on needs permission to do, such as accessing
the content of the current Google Sheet. The user can then grant those
permissions and allow the add-on to proceed. If the
user denies authorization, they can't use the add-on.

Editor add-ons use a different authorization model than
Google Workspace add-ons. Because Editor add-ons operate on
Google Drive files, the editor authorization model defines various
authorization modes that result when add-ons are used with
individual files. When you develop Editor add-ons, understand the
different modes and how an add-on moves between them.

### Authorize published add-ons

After you install a published add-on, the authorization
flow begins:

1. Select an account to install the add-on to when prompted.
2. Review the list of authorizations that the add-on requires. If you grant authorization, select **Allow**. This enables the add-on for use.
3. Run it from the [host application](https://developers.google.com/workspace/add-ons/guides/glossary#host_or_host_application) it extends. If the application is already open in a browser tab, refresh the tab for the add-on to become available.

If the add-on you've installed is later updated and
requires additional authorizations you have not yet granted, the host
application prompts you for those permissions the next time you use the
add-on.

### Authorize unpublished Google Workspace add-ons

![The authorization card prompting for access.](https://developers.google.com/static/workspace/add-ons/images/addon-authorize-access.png)

Unpublished add-ons have a different authorization flow than
published add-ons because they aren't listed in the
Google Workspace Marketplace. After you install an unpublished
add-on, the host application doesn't ask you to
authorize immediately. Instead, the authorization flow starts when you first use
the add-on.

When you run an add-on, it determines if user
authorization is needed. If authorization is necessary, the
add-on presents an authorization card. Authorization is
always required the first time an add-on executes, and
might also be required if a new version of the add-on
uses a service not previously authorized. The
**Authorize Access** button provides a dialog window to Allow or Deny
authorization for the add-on.

> [!NOTE]
> **Note:** If the add-on hasn't yet been [verified](https://developers.google.com/apps-script/guides/client-verification), the [host application](https://developers.google.com/workspace/add-ons/guides/glossary#host_or_host_application) might present additional dialogs and ask you to confirm that you want to continue.

### Authorize non-Google services for a Google Workspace add-on

If your add-on connects to a third-party service, you
must authorize that service separately.

An add-on can connect to a third-party service that
requires authorization. Add-ons that connect to these services
require two separate actions:

- Authorize the add-on itself when it's installed or first started.
- Authorize the non-Google service when it's first accessed.

If an add-on you develop needs to access a non-Google
service using OAuth, configure the connection for that service when you build
the add-on.

For more information, see
[Connect your Google Workspace add-on to a third-party service](https://developers.google.com/workspace/add-ons/guides/connect-third-party-service).

#### Third-party conferencing systems

This section describes authorizing conferencing solutions added to
Google Calendar with a Google Workspace add-on.

**If you don't currently maintain a web-based third-party conferencing system,
your add-on doesn't need to authorize any conference
solutions.** This functionality was built for conference providers specifically.

Add-ons that extend Google Calendar can also add additional
[conferencing solutions](https://developers.google.com/workspace/add-ons/calendar/conferencing/overview) that
let users select a third-party conferencing system when editing
Google Calendar events. If your add-on provides
conferencing options that require the user to log into them, your
add-on must give the user the ability to do so.

If a user attempts to create a conference with your
add-on without a necessary sign in, the conference
solutions's
[`onCreateFunction` method](https://developers.google.com/apps-script/manifest/calendar-addons#ConferenceSolution.FIELDS.onCreateFunction)
should return a
[`ConferenceData`](https://developers.google.com/apps-script/reference/conference-data/conference-data)
object containing a
[`ConferenceError`](https://developers.google.com/apps-script/reference/conference-data/conference-error)
with an
[authentication URL](https://developers.google.com/apps-script/reference/conference-data/conference-error#setauthenticationurlauthenticationurl).

Upon receiving this object, Google Calendar creates a **LOG IN** button in the
event edit UI that links to the
[authentication URL](https://developers.google.com/apps-script/reference/conference-data/conference-error#setauthenticationurlauthenticationurl)
the add-on provides. Users can then use this button to
sign in to the third-party system before they use the
add-on.

See
[Creating third-party conferences](https://developers.google.com/workspace/add-ons/calendar/conferencing/create-conference#handling_errors)
for more details on handling authorization using `ConferenceError`.

### Authorize unpublished Editor add-ons

It's a best practice to
[test Editor add-ons](https://developers.google.com/workspace/add-ons/how-tos/testing-editor-addons)
as you develop them. The authorization flow is identical to that for [published
Editor add-ons](https://developers.google.com/workspace/add-ons/how-tos/starting-addons#authorize-published), except that the flow
starts when you first attempt to test the add-on. If
you later retest the same add-on, you aren't prompted
for authorization again.

## Unauthorize add-ons

When you develop add-ons, unauthorize them to retest the
authorization flow.

To unauthorize an add-on, follow these steps:

1. Open your [account security console](https://myaccount.google.com/permissions).
2. Locate and select the add-on you want to unauthorize.
3. Select **Remove Access**.

When you run the add-on again after unauthorizing it,
the authorization flow is presented again.

## Uninstall add-ons

To uninstall an add-on that you installed from the
Google Workspace Marketplace, refer to
[Uninstall a Marketplace app or add-on](https://support.google.com/marketplace/answer/13988109).

To uninstall an unpublished add-on built in
Apps Script, see the
[testing guide](https://developers.google.com/workspace/add-ons/how-tos/testing-workspace-addons#uninstall).

## Related topics

- [Open and use installed add-ons](https://developers.google.com/workspace/add-ons/guides/using-addons)
- [Connect your Google Workspace add-on to a third-party service](https://developers.google.com/workspace/add-ons/guides/connect-third-party-service)