What is cross-seeding?

Cross-seeding is when you download a torrent from tracker A, and want to seed the files from that download on trackers B and C. This is very useful if you are a member of multiple private trackers and trying to build a ratio or bonus point pool across all of them. Since most trackers share some common releases, you can rapidly build up your ratio/seedpool by cross-seeding all duplicate releases to every tracker you are a member of. You can do this by hand via manually searching for, downloading, and setting the location for each duplicate torrent, but that is tedious and boring, so this guide will show you the basics of how to automate it with cross-seed.

Note: Cross-seeding is primarily for private trackers. Most public torrents let you add new trackers on demand into an existing torrent file, and public trackers don’t care about ratio, so there is little reason to cross-seed to them.

Introducing Cross-Seed

Cross-seed is a tool that automates searching and adding cross seeded torrents to your client. You can run it as a docker service in the background to automate cross seeding torrents that you download. Every time a torrent is finished downloading, it will search your other trackers to find matching releases. If it finds them, it will inject them into your torrent client so you can start cross-seeding immediately.

Cross-seed offers a lot of different options for cross-seeding, so I will not be covering them all here. Please please please read through their documentation as it is very thorough. The goal of this guide is to get you up and running with a basic configuration. By the end of this guide you will:

Have cross-seed setup as a daemon in docker
Have a basic cross-seed configuration that can talk to your prowlarr instance to search for cross-seedable torrents
Have a webhook setup in qbittorrent to trigger cross-seed to search when a torrent has finished downloading
(Optional) Have an autobrr filter set up to automatically push new announces to cross-seed so you can start seeding them immediately

Prerequisetes

This guide assumes you already have some knowledge about torrent clients, prowlarr/jackett, and optionally autobrr.
This guide will be using qBittorrent and prowlarr for examples, but the principles remain the same. Always refer to the Cross-Seed documentation if you have questions about particular configurations.

This guide is targeted at cross-seed v6. They also release new versions, so it is possible that some aspects of this guide may become out of date. Always refer to their official guides.

Having a basic knowledge of JavaScript/programming is useful but not required. The configuration file for cross-seed is in JavaScript, so having a basic understanding of the syntax may help you. In addition, using a text editor that can perform syntax highlighting is useful as well (VIM, Notepad++, etc)

Installation

My preferred method of installation is via Docker. Cross-seed has an in-depth guide on how to get it set up and working using Docker Compose which you can find here . If you don’t want to use docker, they have installation instructions for other platforms there as well such as systemd, unraid, and npm. I won’t rehash every point in their docs, but I will highlight the most important thing to pay attention to:

For Cross Seeding you ideally want to be able to hard-link files so the cross-seeded data doesn’t take up extra space on the drive. This means you NEED to configure your volumes correctly on the cross-seed container so that they match the same structure that your torrent client sees. Check out trash guides for good examples of how you should set up your torrenting/media directories which will work well with cross-seed.

IMPORTANT
If you are using cross-seed via docker, you cannot hardlink between different volumes. Docker treats these as separate filesystems even if they are the same drive on the host machine. See Linking | cross-seed

Configuration

Cross seed provides a ton of options for configuration, so everyone’s end result will be slightly different. I will highlight what I find to be the best options here. All configuration is done in the /config/config.js file (assuming you are using Docker).

Torznab

When a torrent completes, cross-seed will search the torznab feeds you list here for matching torrents from other trackers and inject them into your client. If you copied the default config or let cross-seed create it for you the first time you ran it, your list of torznab feeds will be empty. We want to populate this list with torznab feeds to all the private trackers you wish to cross-seed between.

Assuming you are using Prowlarr, you can get the torznab feed for an indexer by clicking on the Indexer name in the Prowlarr UI, and copying the Torznab URL under the Indexer Details in the modal that pops up. Paste this into your torznab list with your Prowlarr API key like so:

module.exports = {
  // Other cross seed config
  torznab: [
    // my tracker - replace the values in brackets with what is in prowlarr
    `http://{your-prowlarr-host}:{port}/{indexer_id}/api?apikey={yourapikey}`,
    // repeat for the rest of your torznab feeds
  ],
}

You can find your Prowlarr API key under Settings → General in the Prowlarr UI.

Torrent Dir

You only need to change this if you have modified the torrent dir path. If you followed the Docker installation instructions, you shouldn’t need to change this. If you are not using docker, or did not use the recommended docker compose setup, you may need to change this. See the cross-seed docs for more information: Options | cross-seed

qbittorrent URL

The address of your qbittorrent client webui. If you have set up authentication, you will need to include it in the url like so:

module.exports = {
  qbittorrentUrl: `http://username:password@your-qbittorrent-host:port`,
}

Sonarr & Radarr
You can pass links to your sonarr/radarr instances. Cross-seed will use this to search for metadata about releases, giving you better matches. This is a cross-seed v6 only feature.
The config option looks the same as the torznab feed:

module.exports = {
  sonarr: [`http://{your-sonarr-host}:{port}?apikey={yoursonarrapikey}`],
  radarr: [`http://{your-radarr-host}:{port}?apikey={yourradarrapikey}`],
}

You can find your API keys under Settings → General

Data Directories

Providing data directories to cross-seed will help it make data-based matches rather than only being able to compare torrent hashes. This can be useful in finding more matches for the same file whose torrent hashes may be different, but whose data is the same.
If you are using Sonarr/Radarr and following Trash Guides, your data-dirs should look like the following:

module.exports = {
 // only include the directories that contain files that you would want to cross-seed.
 // if you want to cross-seed everything, you can just include `"/data/torrents/"` but 
 // this may have mixed results
 dataDirs: ["/data/torrents/movies", "/data/torrents/tv", "/data/torrents/music"],
}

Recheck

By default cross-seed skips checking that the data actually matches in some cases. If the torrent doesn’t actually match this results in you reporting false stats to the tracker and annoying other users. To avoid this set the skipRecheck option to false.

module.exports = {
  skipRecheck: false,
};

Match Mode

If you are just getting started, I highly recommend using safe (default). This ensures that cross-seed will not add anything that isn’t 100% a match.

Once you are more comfortable, and/or have a good ratio buffer, you can try out partial, which is useful for casting a wider net since some trackers will modify a torrent’s contents which will not pass the safe mode check (adding/removing nfo, screens, samples etc). This does lead to the possibility that you download extra files which is why it’s not the best option if you don’t have a good ratio.

module.exports = {
  matchMode: 'safe',
}

Linking

When cross-seed adds a torrent to your client, the best approach is to have it hardlink the existing files on your harddisk to a new directory so its easy to keep track of what is being seeded from where. This also helps prevent one torrent being removed impacting all the cross-seeded torrents for that file. Cross-Seed’s ability to do this is based on hard linking. Trash Guides has a good reference explaining how and why hardlinking works.

To set up linking, you need to set a couple of properties in your configuration:

module.exports = {
  // the category that this torrent will belong to in your torrent client.
  linkCategory: 'cross-seed-data',  
  // the directory that cross-seed will hardlink your cross-seeded files to
  // Cross-seed v6 will organize these into directories by indexer they were added from, e.g.
  // data /
  //    torrents /
  //       cross-seed /
  //         links/ 
  //           seedpool / 
  //           other-tracker /
  linkDirs: ['/data/torrents/cross-seed/links'], 
  linkType: 'hardlink', // see the cross-seed docs if you want to use symbolic links

}
Its important that your bittorrent client can view this link directory using the same path as cross-seed. When cross-seed injects the torrent into your client, it will attempt to set the save location to the link dir. If your torrent client can’t read it, the injection will fail.

You will need to create the /data/torrents/cross-seed/links directories on your host machine before you start up the cross-seed container.

Output Dir

This is where cross seed will save torrents that it finds to cross seed before injecting them into qbittorrent. I like to keep it in a parallel folder to my link directory. For more information on this, read up on the Direct Client Injection documentation

module.exports = {
  action: 'inject',
  outputDir: '/data/torrents/cross-seed/inject',
}

Like with the linkDir, you will need to create the directories on your host machine before you start up the cross-seed container

RSS/Search Cadence
RSS cadence controls how often cross-seed will pull from your configured torznab feeds. If cross-seed finds a torrent in the RSS feed that can be cross-seeded, it will inject it into your torrent client. If you are using autobrr, you can make this a very long interval or disable it completely. Otherwise, a minimum of 10 minutes is required.

Search Cadence controls how often cross-seed scans your data directory for content and searches your torznab feeds for cross-seeds matching your existing data. I recommend making this a pretty irregular occurrence. We will be setting up a webhook in qbittorrent that will trigger a cross-seed to search every time a torrent finishes downloading, so that combined with subscribing to an RSS feed/autobrr should make search largely unnecessary after the first several scans to backfill your current library of torrents with their cross-seeds. A minimum of 14 days is what I recommend. Once you have most of your existing torrents backfilled, you can increase this number to be even higher.

excludeRecentSearch and excludeOlder prevent cross-seed from slamming trackers with duplicate searches. See the cross-seed documentation for more information on what they do: cross-seed excludeOlder

module.exports = {
  rssCadence: '15min',
  searchCadence: '14 days',
  excludeRecentSearch: '73 days',
  excludeOlder: '365 days' ,
}

Starting Cross-Seed

For the next steps of this guide, cross-seed will need to be running in Deamon Mode. You can start your container by running

docker compose -f <path/to/cross-seed-compose>.yml pull # Update the container to the latest version of cross-seed
docker compose -f <path/to/cross-seed-compose>.yml up -d # Create/start the container
docker logs cross-seed # view the logs and make sure that you have a valid config and the daemon is running

Setting up Qbittorrent Webhook

To better automate cross seeding, we can have our torrent client tell cross-seed whenever it finishes downloading a torrent file. This will then trigger cross-seed to search your other trackers for the same release, and cross-seed it. This serves as a better alternative to searching because it will cross-seed the torrent as soon as it is available on your drive. Refer to the cross-seed documentation

To get started, we’re going to create a shell script that qbittorrent will run after completion. I like to keep this in the qbittorrent config directory, but you can put it wherever you like as long as qbittorrent can see it. I like to call my script after-download.sh to be clear what the script does. Add the following to your script:

#!/bin/bash

# cross-seed. You may need to replace the cross-seed host and port if qbit and cross-seed are not
# running on the same docker network
curl -XPOST http://cross-seed:2468/api/webhook?apikey={{your-cross-seed-api-key}} --data-urlencode "infoHash=${1}"

Double check that your script file can be executed by running chmod +x after-download.sh

Now in qBittorrent, go to Preferences → Downloads → Run External Program

Check the Run external program on torrent finished checkbox, and add the following in the text box:

/bin/bash /config/after-download.sh "%I"
You will need to update the /config/after-download.sh path to be whatever it was you used for your curl script

Finally, read up on Direct Injection in the cross seed docs, as you will need to make sure your output and link directories are configured properly so that both cross-seed and qbittorrent can see the injected torrents (see the configuration options above).

Setting up Autobrr

The last step in this guide will be setting up Autobrr to push all releases to cross-seed to check if you have already downloaded a release as soon as it is announced by a tracker. This can really help your ratio, because if a tracker announces a new release you already have, you can immediately begin cross-seeding it to other people who haven’t downloaded it yet. Since torrents are most active within the first couple minutes they are live on a tracker, this is a GREAT way to build ratio as it gives you lots of free upload.

If you haven’t set up Autobrr with Seedpool, refer to this forum post on how to get started: Quick and Dirty Autobrr Guide

The Autobrr documentation on how to cross-seed is very straightforward, so I’m just going to link it here. Feel free to respond to this post with any questions if you run into trouble: Cross-Seeding with Autobrr

Afterwords

Hopefully this guide was helpful. Cross-seed does take a bit of effort to get setup and configured since it needs to talk to so many things, Prowlarr, your torrent client, autobrr, etc. While we did not explore everything cross-seed can do, this guide should get you to the point where your new torrents are being automatically cross-seeded between trackers. If you have any questions, comments, or feedback, please reel free to drop it in the replies below and I’ll do my best to help out :slight_smile: Happy cross-seeding

Tips and Tricks/Troubleshooting

Container names as hostname
If you are running prowlarr and cross-seed in the same docker network, you can use the container name as the hostname for your torznab urls. This can help reduce network issues from vpns or proxies that may interfere with LAN IPs or other DNS issue, and keeps all the communication between containers within your docker network. For example, if my prowlarr container name is prowlarr, then I can change my torznab url in my cross-seed config file from http://prowlarr.mydomain-or-ip.com/api/1?apikey=myapikey to http://prowlarr:9696/api/1?apikey=myapikey

Cross Seed and Freeleech

Its common for people to set a “Freeleech Only” option in their prowlarr indexer if they are new to a tracker and trying to build ratio. Be careful when using a “Freeleech Only” indexer with cross seed, because you might be missing out on a bunch of cross-seedable torrents that aren’t available in that indexer’s freeleech offerings! A workaround is to create a second indexer with a specific cross-seed sync profile which has automatic searching disabled. This will stop other *arr apps from downloading from it, but can be used by Cross-Seed to search all an indexer’s torrents for matching cross-seeds. Remember, if you are using matchMode: ‘safe’ in cross-seed, cross-seed will never add a torrent that requires you to download something from the tracker, making it safe to use without worrying about freeleech while you build your ratio.

Here is what a cross-seed sync profile would look like in Prowlarr:

Edits
Added info about outputDir and direct client injection
Added Tips and Tricks