BitTorrent client and library in Go. Running in production at put.io.

• Core protocol
• Fast extension
• Magnet links
• Multiple trackers
• UDP trackers
• DHT
• PEX
• Message stream encryption
• WebSeed
• Fast resuming
• IP blocklist
• RPC server & client
• Console UI
• Tool for creating & reading .torrent files

If you are on MacOS you can install from brew:

brew tap cenkalti/rain
brew install rain

Otherwise, get the latest binary from releases page.

Rain is distributed as single binary file. The main use case is running rain server command and operating the server with rain client <subcommand> commands. Server consists of a BitTorrent client and a RPC server. rain client is used to give commands to the server. There is also rain client console command which opens up a text based UI that you can view and manage the torrents on the server. Run rain help to see other commands.

Rain is the main BitTorrent client used at put.io. It is designed to handle hundreds of torrents while using low system resources. The main difference from other clients is that Rain uses a separate peer port for each torrent. This allows Rain to download same torrent for multiple accounts in same private tracker and keep reporting their ratio correctly.

• IPv6 tracker extension
• IPv6 extension for DHT
• uTorrent transport protocol
• Superseeding
• HTTP seeding
• Merkle tree torrent extension
• uPnP port forwarding
• Selective downloading
• Sequential downloading