Transmission

Transmission is a free, open-source BitTorrent client with a native Mac interface. It downloads and shares files through the BitTorrent peer-to-peer protocol and is useful for distributing authorised material such as open-source operating-system images, public datasets and your own files. The client does not supply a content subscription or grant rights to material shared by other people.

Features

• Open .torrent files and magnet links and monitor transfer progress.
• Manage download locations, selected files and transfer queues.
• Set bandwidth limits and configure advanced transfer preferences.
• Inspect peers, trackers and transfer information.
• Use watch folders, blocklists and optional remote control.
• Manage a running Transmission instance through its Web interface or RPC clients.

Installation and first use

Install the Mac app with brew install --cask transmission, or download the official DMG and move Transmission.app to Applications. Open a torrent file or magnet link from a source you trust, choose the destination and review the files before starting. Make sure you have permission to receive and redistribute the content. BitTorrent transfers can upload pieces to other peers while downloading and continue seeding afterward; configure upload limits and stopping conditions to suit your connection.

The Mac application is ready to run without installing a compiler, a separate Java runtime or the server daemon. The Cask declares no extra formula dependency and conflicts with the beta and nightly Transmission Casks. The daemon and transmission-remote CLI are separate upstream variants; they are not required for ordinary local use of this Mac application. Network availability, peer availability and tracker policies affect transfer speed and completion.

Requirements and platforms

The tagged 4.1.3 Xcode project sets a macOS 11 Big Sur deployment target. The native Mac application supports Apple Silicon as well as Intel workflows; upstream also provides Windows, Linux/BSD graphical clients and a headless daemon for server/router use. These interfaces differ and the Mac Cask is not a Windows or Linux installer. The recorded Cask does not specify an additional macOS minimum, so use upstream release requirements rather than assuming every historic system is supported.

The official Mac DMG for 4.1.3 is 11,186,296 bytes, confirmed by its GitHub release asset. This is only the client download size. Allow storage for your selected content and partial downloads; no universal RAM or content-space minimum applies to every torrent.

Remote access

Remote control is optional. If you only manage transfers on this Mac, leave Enable remote access off. To use it, open the Remote preferences, enable the service, choose its port, enable password protection and restrict access to trusted addresses. Use Launch web interface locally or connect an authorised remote client to the configured host and port. This controls an existing running Transmission instance; it is not an account hosted by the Transmission project.

Web/RPC access and BitTorrent peer traffic are separate services. RPC credentials and allowlists protect the management interface; they do not make peer-to-peer transfers anonymous. Authentication is configurable and must not be assumed simply because remote access is enabled. The official 4.1.3 release fixes a CORS issue that exposed the anti-CSRF nonce and specifically encourages remote-access users to upgrade. Keep access limited to an appropriate trusted network and use a secure access path when accessing the service remotely.

Accounts, cost and license

Transmission is free, volunteer-developed software with no paid feature tier or mandatory project account. A particular private tracker or content source may impose its own login, ratio and usage rules. Those accounts are separate from Transmission's optional local remote-control username and password.

The official COPYING file permits redistribution and modification under GNU GPLv2 or GPLv3, or a future license endorsed by Mnemosyne LLC, with an OpenSSL linking exception. Some individual source files have more permissive terms. The client license covers the software; it does not change the licensing or copyright of transferred files.

The image is the official website's Mac dark-mode example, showing an Ubuntu 21.10 transfer and the inspector. It is an illustrative upstream screenshot, not a fresh capture of version 4.1.3.

Sources: Official overview, Tagged project README, 4.1.3 release, Tagged Mac remote-access help, RPC configuration, Mac build target, License.