An open-source BitTorrent library that runs on all platforms supporting the .NET Platform Standard 2.0.


TorrentCore is designed to be easy to use, while supporting more advanced features if required.

var client = new TorrentClient();
var download = client.Add("sintel.torrent",
await download.WaitForDownloadCompletionAsync();

Extensible and Modular

TorrentCore is designed to allow custom extensions to be added and parts of the built-in functionality to be swapped out. Below are some examples of the ways in which functionality can be added or changed.

The public interface for extensions is unstable and subject to change while TorrentCore is under pre-release development.

Custom Transport Protocol

TorrentCore includes built-in support for communicating with peers over TCP. You can add support for any custom communication protocol that is able to expose connections to peers as a System.IO.Stream. (Of course, protocols other than TCP and uTP are incompatible with other BitTorrent clients.)

For more information, see custom transport protocols.

BitTorrent Extension Protocol

Custom BEP 10 message handlers can be provided by implementing an IExtensionProtocolMessageHandler. You can then register your custom extension message handler to handle custom message types.

For more information, see custom extension protocol messages.


Modules are a general-purpose low-level mechanism to add functionality by hooking into events. Examples of things that modules can do include:

  • Modify the connection handshake sent to peers
  • Add a new type of message
  • Send raw BitTorrent messages to peers
  • Override the behaviour of messages built into the BitTorrent protocol itself

Some of the core functionality is implemented through modules, including the BEP 10 extension protocol. For more information, see custom modules.

Pipeline Stages

When a torrent is started, it is managed by a number of sequential stages in a pipeline that take it from checking the existing downloaded data to seeding to other peers. New stages can be added to the pipeline and built-in stages can be swapped for custom implementations.

For more information, see pipeline stages.

Data Storage

The file data for torrents is usually stored on disk. TorrentCore includes mechanisms to store the data on disk and in-memory, but you can provide custom storage mechanisms by implementing an IFileHandler.

For more information, see data storage.

Piece Picking Algorithms

A custom algorithm for deciding which pieces to request from peers can be used by implementing an IPiecePicker.

For more information, see piece picking.

Web UI

TorrentCore includes an optional web UI that can be used for detailed monitoring of Torrent downloads. It does not provide any functionality to control downloads.

It can be enabled by referencing TorrentCore.Web and calling:


This starts a web interface on http://localhost:5001/.


The web interface requires .NET Platform Standard 1.6.

Command-Line Client

In addition to a library, TorrentCore provides a basic command-line client for downloading torrents. Usage is as follows:

torrentcorecli --help

usage: torrentcorecli [-p <arg>] [-o <arg>] [-v] [--ui [arg]] [--]

    -p, --port <arg>      Port to listen for incoming connections on.
    -o, --output <arg>    Path to save downloaded files to.
    -v, --verbose         Show detailed logging information.
    --ui [arg]            Run a web UI, optionally specifying the port
                          to listen on (default: 5001).
    <input>               Path of torrent file to download.


Contributions are welcome! Please submit a pull request.