How to Open XPI Files

By Daniel Tolliday

You will need to have a copy of the Mozilla Firefox web browser installed on your computer, prior to attempting to open an .XPI extension file. This program can be downloaded for free from Mozilla's website (See "Resources" section for link). The .XPI extension file is a compressed file used for installing various applications within the Firefox program--such as a new skin for your web browser. These files are simple to open and install, even for the most inexperienced of Internet users.

Things You'll Need

  • Mozilla Firefox Web Browser

Step 1

Locate the application or add-on that you wish to use. Open a new Firefox window and click "Tools" then "Add-ons". A smaller window will appear, giving you a list of reccommended .XPI files to choose from. You will also be given the option to search for them.

Step 2

Enter some keywords into the search box. For example, if you are wanting to open an application that allows you to access Java-based web games, type in "Java", and a list of options will appear.

Step 3

Search through the list and find an option that suits your preferences. You can view information on each application before choosing one. Select "Add to Firefox" once you have found the application you wish to open.

Step 4

Select "Install Now" to confirm your intention to install and open the application file. The file will download within your Firefox browser--and it won't matter which version of Windows you are currently operating.

Step 5

Click "Restart Firefox" once the installation has been completed and your browser will save the open web pages and re-open them once it restarts.

Step 6

Open your new .XPI file application by clicking "Tools" then "Add-ons." You will see four options at the top of the small window. Depending on the type of application, it will be under Extensions, Themes or Plug-ins. Double-click the appropriate application and you will then be able to use it.

Tips & Warnings

  • If attempting to access an .XPI application file from an outside source, ensure you check the legitimacy of the file before downloading and opening it.