The File Extensions Database


.XPI File Extension

  • Developer by: Mozilla
  • Category: Plugin Files
  • Format: Zip

What is an .XPI file?

.XPI is Cross-platform Installer Package

An XPI file is a compressed installation archive used by various Mozilla applications, including Firefox, Thunderbird, and SeaMonkey. It contains software, such as a web browser plugin, extension, or theme. XPI files also include an install.js or install.rdf file, which contains the installation instructions.

Some versions of Firefox allow you to install XPI files may by simply dragging and dropping the file onto an open web browser window. The Mozilla software uses a component called XPInstall, (which includes Mozilla installer script) to install the XPI packages.

If dragging and dropping the XPI file does not work, you can install the file in Firefox following the instructions below:

  • In Windows, select the Menu (three horizontal line) icon in the upper-right corner and click Add-ons (select Tools → Add-ons in macOS).
  • Select Extensions, Themes, or Plugins.
  • Click the gear icon dropdown menu and select Install Add-on From File....
  • Navigate to and choose your XPI file and click Open.
  • Here are instructions for installing an XPI file in Thunderbird:

  • In Windows, select the Menu (three horizontal lines) icon, click Add-ons, then Add-ons again (select Tools → Add-ons in macOS).
  • Select Extensions, Themes, or Plugins.
  • Click the gear icon dropdown menu and select Install Add-on From File....
  • Navigate to and choose your XPI file and click Open.
  • Since an XPI file is Zip-compressed, you can manually extract the contents in the file by renaming the .xpi extension to .zip then extracting the contents with a Zip compression utility, such as Corel WinZip, 7-Zip, or Apple Archive Utility. You most likely will find a .JAR file, which is typically used for containing the software to install, and an install.js or install.rdf file.

    Programs that open Cross-platform Installer Package
    Windows
    Mozilla Firefox
    Mozilla Thunderbird
    Mozilla SeaMonkey
    Mac
    Mozilla Firefox
    Mozilla Thunderbird
    Mozilla SeaMonkey
    Linux
    Mozilla Firefox
    Mozilla Thunderbird
    Mozilla SeaMonkey

    How to solve problems with XPI files

    • Associate the XPI file extension with the correct application. On :
      Windows: Right click on any XPI file and then click "Open with" > "Choose another app". Now select another program and check the box "Always use this app to open *.XPI files". Mac: Right click (or Ctrl-click) the XPI file, then click "Open with" > "Other...". Then choose another program and check the "Always Open With" box. Linux: Right click on the file, and select "Open with" and choose another program. iPhone: Tap the file. If you do not see an app to open the file, then tap Share "Share" and choose an app. Alternatively, save the file. Then open the Files app Files app. There long-press on the file, then release your finger. You will see a black menu bar. Then tap "Share" and select an app. Android: Tap the Settings icon on your smartphone, then tap on the Apps section. There tap the Options icon in the top right-hand corner of the screen to change the default apps.
    • Update your software that should actually open .XPI is Cross-platform Installer Package. Because only the current version supports the latest XPI file format. Search, therefore, e.g. on the Mozilla manufacturer website after an available .XPI is Cross-platform Installer Package update.
    • To make sure that your XPI file is not corrupted or virus-infected, get the file again and scan it with antivirus software.