# libtorrent — High-Performance C++ BitTorrent Library

> libtorrent is a feature-complete C++ implementation of the BitTorrent protocol. It powers popular clients like qBittorrent and Deluge, providing efficient peer-to-peer file transfer with extensive protocol support.

## Install

Save as a script file and run:

# libtorrent — High-Performance C++ BitTorrent Library

## Quick Use
```bash
# Install via package manager
sudo apt install libtorrent-rasterbar-dev  # Debian/Ubuntu
brew install libtorrent-rasterbar           # macOS
vcpkg install libtorrent                    # vcpkg
# Python bindings:
pip install libtorrent
```

## Introduction
libtorrent (libtorrent-rasterbar) is a C++ library implementing the BitTorrent protocol with a focus on performance and standards compliance. It serves as the engine behind popular torrent clients and is used in both desktop and embedded applications.

## What libtorrent Does
- Implements the full BitTorrent protocol including DHT, PEX, and magnet links
- Manages concurrent downloads with disk caching, piece prioritization, and rate limiting
- Supports protocol extensions including uTP (micro transport protocol) for low-overhead transfers
- Provides Python bindings for scripted torrent management and automation
- Handles web seeding (HTTP/FTP sources) alongside peer-to-peer transfers

## Architecture Overview
libtorrent uses an async I/O model built on Boost.Asio. A session object manages all torrents, coordinating peer connections, disk I/O, and bandwidth allocation. The disk subsystem uses memory-mapped files and an LRU cache to minimize system calls. Each torrent runs its own piece picker and choking algorithm.

## Self-Hosting & Configuration
- Link against libtorrent-rasterbar via CMake with find_package(LibtorrentRasterbar)
- Create a session with settings_pack to configure ports, rate limits, and connection caps
- Add torrents via .torrent files, magnet URIs, or in-memory resume data
- Tune disk cache size and hashing threads for your storage hardware
- Enable encryption, DHT, and local peer discovery in settings

## Key Features
- Powers qBittorrent, Deluge, and other widely used torrent clients
- uTP transport reduces network congestion while maintaining throughput
- Full DHT implementation with BEP-44 mutable items for decentralized data storage
- Efficient memory-mapped disk I/O with configurable caching strategies
- Supports seeding, super-seeding, and web seeding from HTTP sources

## Comparison with Similar Tools
- **libtorrent (Rakshasa)** — Rakshasa's libtorrent powers rTorrent; libtorrent-rasterbar offers broader protocol support and Python bindings
- **Transmission** — Transmission is a full client; libtorrent is an embeddable library for building custom clients
- **aria2** — aria2 is a multi-protocol downloader; libtorrent specializes in BitTorrent with deeper protocol features
- **WebTorrent** — WebTorrent runs in browsers via WebRTC; libtorrent targets native applications with system-level performance

## FAQ
**Q: What is the difference between libtorrent and libtorrent-rasterbar?**
A: libtorrent-rasterbar (by Arvid Norberg) is the widely used library powering qBittorrent and Deluge. A separate, older project by Rakshasa powers rTorrent.

**Q: Does libtorrent support magnet links?**
A: Yes. libtorrent fully supports magnet links, downloading metadata from the DHT or peers before starting the transfer.

**Q: Can libtorrent be used in commercial software?**
A: Yes. libtorrent uses a BSD license, allowing unrestricted commercial use.

**Q: What platforms does libtorrent support?**
A: Linux, macOS, Windows, FreeBSD, and Android. Any platform with a C++17 compiler and Boost.

## Sources
- https://github.com/arvidn/libtorrent
- https://libtorrent.org/

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Source: https://tokrepo.com/en/workflows/asset-64c0432f
Author: Script Depot