worked for me

Not an extension, just a link to a converter site. Converter site requires either paid access or disabling your ad blocker. Save yourself time and privacy - use a different site or extension.

유튜브 영상을 MP4로 빠르게 저장할 수 있어서 꽤 편리합니다. 복잡한 사이트 들어갈 필요 없이 영상 페이지에서 바로 다운로드할 수 있는 점이 마음에 들었어요. 다운로드 과정도 단순하고 화질 선택도 쉬워서 자주 쓰게 되는 확장 프로그램입니다.

Makes you pay to download a playlist.

This is a great and super convenient Firefox add-on. It makes downloading YouTube videos to MP4 really quick and straightforward with no complicated steps. Everything feels smooth and easy to use, even for first-time users. I like how fast it works and how it keeps things simple without extra clutter or confusing settings. For saving videos for offline viewing, it’s very practical and reliable in my experience. Definitely a 5-star tool for anyone who needs quick downloads from YouTube.

Another downloader that doesn't work. YouTube has delcared all out war on downloaders like this one and others like it. None of the downloaders I've used appear to be working either. This is as of 01/26/2026...
If the developer isn't going to fix it or doesn't intend to, then remove it...