How to open .XPI files on Android
To open .XPI files on Android, android Firefox support for installing .xpi varies by Firefox channel/build; if installation is not offered, transfer the file to a desktop Firefox or inspect it as a ZIP archive.
Step-by-step instructions
- Android Firefox support for installing .xpi varies by Firefox channel/build; if installation is not offered, transfer the file to a desktop Firefox or inspect it as a ZIP archive.
Common issues
Firefox won’t install the XPI (blocked or incompatible)
Firefox may refuse an XPI if it is not compatible with your Firefox version or if installation from a file/source is restricted. Extension packaging and compatibility expectations changed significantly around Firefox 4 and later.
- Confirm the add-on is intended for your Firefox version and extension type (legacy vs. WebExtension packaging).
- Try installing through Firefox’s add-ons manager rather than treating it as a regular file.
- If it still fails, inspect the XPI as a ZIP to verify it contains the expected extension files/metadata.
The XPI downloads but doesn’t install from a website
Web servers may need to serve .xpi with the expected MIME type so browsers recognize it as an installable add-on package instead of a generic download.
- If you manage the website, configure the server to send the MIME type commonly used for XPI: application/x-xpinstall (as documented by Mozilla).
- If you are a user, save the file and use Firefox’s add-on installation flow; if that still fails, the add-on may be blocked or not compatible.
Archive tools say the file is corrupt or won’t open
An XPI is a ZIP archive; if download was interrupted or modified, ZIP tools may fail to read it.
- Re-download the .xpi from its original source to ensure it is complete.
- Try opening it with another ZIP-capable tool to confirm whether the archive is actually damaged.
- If it opens, extract to a folder rather than trying to view-in-place.
Signature-related problems (unsigned or signature missing)
Firefox add-ons use signing artifacts inside the XPI (for example under META-INF) and Firefox may enforce signing requirements depending on configuration/version.
- Inspect the XPI contents as a ZIP and check for signature-related files (such as entries under META-INF) if you are troubleshooting.
- If Firefox requires signed add-ons, obtain a properly signed build from a trusted source rather than trying to bypass checks.
Security note
Treat .xpi files as executable add-on packages, not just “documents”: installing an untrusted XPI can grant code running in the browser significant capabilities.