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

  1. Go to Outlook in Office 365.

  2. Choose the gear icon in the top-right section 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. 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 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, 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.