Download Castorus

Name: Castorus
Author: Castorus

By: Castorus

Download Castorus (current and past versions) for Firefox

Latest Version: 5.22 Updated: 22 days ago

Ready to install?

Castorus is available to install from Firefox Add-ons Store and for download from this page.

View source code

4,770

Daily users

4.1

78 ratings

Total downloads

Available versions

You can find the current and older versions of Castorus here. You can download the archived versions or inspect their source codes.

As a free user, you can download up to 3 latest versions.

Upgrade to download older versions

Version	Download	Size	Timestamp
5.22	XPI · ZIP · Source code	180.13KB	2026-06-19
5.21	XPI · ZIP · Source code	180.08KB	2026-06-05
5.11	XPI · ZIP · Source code	177.75KB	2026-02-03
4.0.61	Paid users only	39.65KB	2023-09-15
4.0.6	Paid users only	36.37KB	2021-09-21

2026-06-19 · 0 downloads

XPI ZIP Source code

2026-06-05 · 0 downloads

XPI ZIP Source code

2026-02-03 · 0 downloads

XPI ZIP Source code

2023-09-15 · 0 downloads

Paid users only

2021-09-21 · 0 downloads

Paid users only

Install XPI file

An XPI file, short for "XPInstall," is a compressed file format used primarily by Mozilla applications, like Firefox and Thunderbird, to distribute and install add-ons or extensions. These files are similar in function to CRX files for Chrome but cater to the Mozilla ecosystem.

Simply drag-and-drop the XPI into Firefox to install the add-on.

Install ZIP file

Download the Castorus ZIP file.
In Firefox browser, go to about:addons to open Add-ons Manager
Click on ⚙, Install Add-on From File
Select the Castorus ZIP file from step 1. Castorus is now installed on your browser.