A magnet link is a type of hyperlink that enables the downloading of files and data from P2P sharing networks, particularly torrent networks. It works in a server-less environment and contains all the information a torrent client requires to download a specific file.
The magnet link was designed to replace and upgrade torrent file specifications.
The magnet link was initially introduced to eliminate the additional workload from torrent hosting/online storage providers. It is preferable to a .torrent file because it eliminates the need to download a tracker file and search for uploading peers.
A magnet link replaces a .torrent file extension/mechanism with only a hyperlink, which consists of the magnet identifier, file name and cryptographic content hash. The content hash, which works like an ISBN number, is derived from the actual file to uniquely identify a file/data on multiple hosts. Once the user clicks a magnet link, its data is sent to the desktop torrent client software, which automatically starts the download.
A magnet link is also important in safely facilitating the compliance of online file sharing services, including copyright regulation, as the link does not actually provide the file but points to its location.