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 in Office 365

The process for sideloading an add-in in Outlook in Office 365 depends upon whether you are using the new Outlook on the web or classic Outlook on the web.

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

  1. Open Outlook 2013 or later on Windows, or Outlook 2016 or later on 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.