You can easily add magnet protocol association in Mozilla Firefox browser for any bittorrent client. Transmission is a fast and easy BitTorrent client. From the wikipedia:
The Magnet URI scheme is a de facto standard (instead of an open standard) defining a URI scheme for Magnet links, which mainly refer to resources available for download via peer-to-peer networks. Such a link typically identifies a file not by location, but by content — more precisely, by the content’s cryptographic hash value.
How can I add magnet support to Firefox?
Open firefox. Type the following in address bar:
about:config
Sample outputs:
Click on “I’ll be careful, I promise!” button. Right click > New > Boolean (see fig.02):
You need to enter new boolean value called network.protocol-handler.expose.magnet and set it to false. This allows you to assign a bittorrent client for all magnet links. For example, when you open a magnet link you will be prompted with a Launch Application dialogue box. From there you can simply select transmission or any other torrent client.

How do I force Firefox to open all magnet links via transmission bittorrent client only?
Just click on a magnet link and Firefox will be forced to prompt you as follows:
You need to specify the full path as follows:
/usr/bin/transmission
Check out related media
This tutorial also available in video format:
See also
- firefox(1)
- Transmission bittorrent client runs natively on multiple operating systems.
What is the point of adding a tutorial for a version of firefox that is badly outdated?
This method by no means will work on any linux distro that is is not 3 years old.
Latest versions of firefox seem do not use network.protocol.handler* keys at all.
To the people from the future:
Right way to add new protocol handler is to edit either /usr/share/applications/mimeinfo.cache or edit the .desktop file of the application you want to be a handler for a specific resource.
For example here is a relevant excerpt from /usr/share/applications/qBittorrent.desktop
MimeType=application/x-bittorrent;x-scheme-handler/magnet;
yeah its two years later and I still found this post to be helpful
Thank you very much for this! It works perfectly on my Firefox 16 on Kubuntu 12.04!
Thank you for sharing!
thanks a lot, this worked perfectly! so much easier than all the other crap i thought i’d have to do to get magnet links going.
Well it did work great in Iceweasel 14.0.1, preinstalled in AVLinux 6.0 (2012)… Thanks a lot !
it worked, thanks.
To raravun, it didnt work for you so bug off.
Thanks for this. I have used transmission before on Ubuntu and have not had the problem I had just now when I updated to 13.04. Got transmission to work now when I add torrents. Thanks for the info…
Thanks a lot!! :)
Thank you for this tutorial. It worked for me using Transmission 2.77 and Firefox 22 in Linux Mint 15 KDE.
This worked perfectly for me, thanks so much!
Mint 15
Hey Man,
Thanks very much. It solved my problem perfectly!
Reguards from Brazil
Great! Very Helpful for what I needed!!!
Thank you very very much sir it worked perfectly. This is exactly what I was looking for!
Tanks!
Thanks very much.
Simple and works.
Ubuntu 12.04
It worked. Thank you so much. Ubuntu 12.04 lts
thanks, worked great on Arch with Firefox 33 Aurora
Worked perfectly. Thanks for the tutorial
Thanks a lot. worked great on Firefox 32
Pls how do I do this on windows computer? thank you
This worked for me, FF 47, Debian 9, KDE 5:
1. In about:config find “network.protocol-handler.expose-all”, change to “false”;
2. Click on some magnet link – a file browser pop-up should appear, show it full path to the executable (/usr/bin/qbittorrent for ex.);
3. Change “network.protocol-handler.expose-all” back to “true”;
4. Download the world.