Sideload Outlook add-ins for testing

You can use sideloading to install an Outlook add-in for testing without having to first put it in an add-in catalog.

Sideload an add-in in Outlook on the web

The process for sideloading an add-in in Outlook on the web depends upon whether you are using the new or classic version.

Note

If your organization has included its logo in the mailbox toolbar, you might see something slightly different than shown in the preceding images.

Sideload an add-in in the new Outlook on the web

  1. Go to Outlook in Office 365.

  2. In Outlook on the web, create a new message.

  3. Choose ... from the bottom of the new message and then select Get Add-ins from the menu that appears.

    Message compose window in the new Outlook on the web with Get Add-ins option highlighted

  4. In the Add-Ins for Outlook dialog box, select My add-ins.

    Add-Ins for Outlook dialog box in the new Outlook on the web with My add-ins selected

  5. Locate the Custom add-ins section at the bottom of the dialog box. Select the Add a custom add-in link, and then select Add from file.

    Manage add-ins screenshot pointing to Add from a file option

  6. Locate the manifest file for your custom add-in and install it. Accept all prompts during the installation.

Sideload an add-in in classic Outlook on the web

  1. Go to Outlook in Office 365.

  2. Choose the gear icon in the top-right section of the toolbar and select Manage add-ins.

    Outlook on the web screenshot pointing to Manage add-ins option

  3. On the Manage add-ins page, select Add-Ins, and then select My add-ins.

    Outlook on the web store dialog with My add-ins selected

  4. Locate the Custom add-ins section at the bottom of the dialog box. Select the Add a custom add-in link, and then select Add from file.

    Manage add-ins screenshot pointing to Add from a file option

  5. Locate the manifest file for your custom add-in and install it. Accept all prompts during the installation.

Sideload an add-in in Outlook on the desktop

Outlook 2016 or later

  1. Open Outlook 2016 or later on Windows or Mac.

  2. Select the Get Add-ins button on the ribbon.

    Outlook 2016 ribbon pointing to Store button

    Note

    If you don't see the Get Add-ins button in your version of Outlook, select the Store button on the ribbon instead.

  3. Select Add-Ins, and then select My add-ins.

    Outlook 2016 store dialog with My add-ins selected

  4. Locate the Custom add-ins section at the bottom of the dialog. Select the Add a custom add-in link, and then select Add from file.

    Store screenshot pointing to Add from a file option

  5. Locate the manifest file for your custom add-in and install it. Accept all prompts during the installation.

Outlook 2013

  1. Open Outlook 2013 on Windows.

  2. Select the File menu, then select the Manage Add-ins button on the Info tab. Outlook will open a browser.

  3. Follow the steps in the Sideload an add-in in Outlook on the web section according to your version of Outlook on the web.

Remove a sideloaded add-in

To remove a sideloaded add-in from Outlook, use the steps previously described in this article to find the add-in in the Custom add-ins section of the dialog box that lists your installed add-ins. Choose the ellipsis (...) for the the add-in and then choose Remove to remove that specific add-in.