Support for MP4 Downloader has been discontinued.

I don't have the time anymore to keep up with all the breaking changes that Mozilla is making in add-on development for Firefox, in addition to reacting to changes in YouTube, Dailymotion, and Vimeo that affect video downloading. Since Mozilla dropped support for traditional add-ons in November 2017, MP4 Downloader has stopped working entirely in new versions of Firefox.

The codebase has been left in the middle of a complete rewrite (see the Source Code section of the Development page), although this rewrite is not anywhere close to what is required to support new versions of Firefox. That codebase, and this website, are left here for archival purposes.

To all MP4 Downloader fans, thanks for many years of support.

--Jake Hartz


Versioning and Release Schedule Terminology

There are two main categories of MP4 Downloader versions: released versions and pre-release versions. The released versions are deemed stable for normal use; the latest released version is available for download on the download page.

Any MP4 Downloader version that is not yet released (ie. not the version available for download on the download page) is considered a "pre-release" version. There are two types of pre-release versions:

Source Code

The source code for the MP4 Downloader Firefox add-on, the MP4 Downloader bookmarklet, and the MP4 Downloader website (including this page) is located in the git repository on GitHub:

To contribute to any of these sections of the MP4 Downloader source code, just fork the repo and send a pull request.

Developer Documentation

Documentation used in the development of MP4 Downloader is located on the wiki.

Version Numbers

The version numbers for the MP4 Downloader add-on, starting with the release of MP4 Downloader 2.0.0:

Git Branching and Tagging