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

  1. Go to Outlook on the web.

  2. Choose the gear icon in the top-right section and select Manage integrations.

    Outlook on the web screenshot pointing to Manage integrations option

  3. On the Manage integrations page, select Add-Ins, select the Click here to add a custom add-in link, and then select Add from file....

    Manage integrations screenshot pointing to Add from a file option

  4. 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 2016, Outlook 2013, or Outlook 2016 for Mac.

  2. Select the Store button on the ribbon.

    Outlook 2016 ribbon pointing to Store button

  3. On the Store page, select Add-Ins, select the Click here to add a custom add-in link, and then select Add from file....

    Store screenshot pointing to Add from a file option

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