Published on August 25, 2020 by SatoshiVPN in Protocols.

How BitTorrent works

Learn all about the decentralized peer-to-peer file sharing protocol, BitTorrent.

How BitTorrent works

BitTorrent isn't a program at all. It's a method for downloading files using a peer-to-peer distributed file-sharing system. However, you're probably familiar with BitTorrent clients like uTorrent and BitTorrent—the programs you use to download files via the BitTorrent protocol.

What makes the BitTorrent protocol special is that it distributes a file's source host from a single server to all the other users simultaneously downloading a file at any given time. This increases network efficiency because you're able to download a shared file directly from other users—skipping an intermediary server in the process. And because BitTorrent splits up and distributes hundreds of tiny pieces of files, you don't even need to have the entire file downloaded before sharing.

As long as you have a piece of the file, you can begin sharing it with others. That's what makes files on BitTorrent so fast to consume; users can exchange tiny pieces of files with each other as soon as they've been downloaded (rather than awaiting the full download to be finished).

Let's try visualizing a typical file exchange to or from a website:

If you download something from BitTorrent, it looks a bit like this:

The advantage? If one peer in the large group of BitTorrenters is slow, that's all right—luckily, there will be other peers in the network which will give you the bits of the file you're searching for at a much faster rate. By contrast, when you download a file from a single slow server, you'd be stuck.

BitTorrent pieces files together from many users simultaneously, making the likelihood of a fast download more common than a single host—and you yourself would even help contribute to the requests of others.

Finding and downloading a file with BitTorrent

Now that you have a better understanding of BitTorrent's distributed network and how that helps to speed up file sharing, let's jump straight into the use.

1. You must download a BitTorrent client

You cannot participate in a BitTorrent file exchange without a BitTorrent client. Fortunately there are plenty of BitTorrent clients to choose from. Here's a few of the most popular clients:

μTorrent — Most popular overall. Works on all devices.
qBitTorrent — Open-source alternative to μTorrent.
Transmission — Popular amongst Mac users and very user friendly.

Once you have your client installed, you'll need to find a .torrent file that your BitTorrent client will connect to. It's important to note that a .torrent file does not include the end file you are hoping to download. Actually, .torrent files include information that informs the BitTorrent client where it can locate peers who also share and download the target file. More on finding torrents next.

2. Finding torrents

It's here where we get into a legal gray area. Let's be serious for a minute: many users share files protected under copyright using BitTorrent. Piracy and BitTorrent go hand to hand, regardless of how much we deceive ourselves that we're just downloading Linux distributions and screensavers. We recommend you treat this warning with care because should you decide to download copyright content, you may be held responsible for your actions.

Whatever material you're searching for, we encourage you not to use the method, "Google the name plus the term 'BitTorrent'", unless you're genuinely aiming for something like a standard Linux distribution. If you're trying to get your favorite TV shows for free, you'll risk ending up on a spammy site intending to take advantage of you. Eventually, you could end up BitTorrenting a file that is not, in the slightest way, what you anticipated.

We recommend starting out with The Pirate Bay or rarbg. Stick with popular suggestions from others already on these torrent search engines—it's more likely they are working with a trustworthy torrent. You can tell if a torrent is popular based on how many seeders it has. (i.e. how many users have complete copies of what you'd like to download.) If the number of seeds is 0, you may want to move on to the next available torrent. Aim for torrents with dozens of seeders or more.

3. Downloading torrents

All you need to do to get downloading is to execute a .torrent file using your BitTorrent client. However, we recommend a faster and more popular method: check the torrent listing for a magnet icon. The magnet represents a short link to what is known as a "magnet connection." The distinction here is that you aren't accessing a .torrent file directly from a server; rather, the magnet link provides all the details you need to seek that .torrent file from other BitTorrent peers. In other words, the magnet link is a decentralized technique that lets you skip downloading a .torrent file to get going.

Simple enough? There are few more considerations that we recommend you consider when you start your BitTorrent journey:

Set bandwidth limits
Most BitTorrent clients have a way of rate-limiting the bandwidth used to connect to the BitTorrent network. When you're sharing your internet connection for hours with someone else that could interfere with your work on other applications. So, setting bandwidth limits is essential.

Use a VPN
Even if everything you download is legitimate in your location, your network history is exposed. Don't believe us? Try entering your IP address in this website that tracks peers on the BitTorrent network:—it's more than Big Brother and your ISP who are watching. It could be anyone. But don't use a free VPN. Pay for a great VPN which will mask your home network and give you the fastest connection speeds, like SatoshiVPN.

Seed for however long you're comfortable
Though keeping a perfect BitTorrent ratio (the amount you download vs. how much you upload to others) is noble and good for you, go back to the first concern. If you're seeding files all of the time, your network functioning could be affected. In particular, we recommend considering whether you want to start your BitTorrent client while starting your machine (and instantly begin seeding everything that you have downloaded).

Important considerations: BitTorrent and piracy

It's generally assumed that BitTorrent promotes piracy by providing people with an easy and inexpensive way to share copyright videos, music tracks, and other media without having to pay—and indeed it is unlawful to download items that are protected by copyright without paying the holders for the privilege.

If you commit to legitimate files not protected under copyright, you will do nothing wrong. In a real sense, you are helping to strengthen the network by providing another seed for which others in the network can connect.


BitTorrent has its terminology. Some of the standard terms associated with BitTorrent include:

Leeches - People who download files but don't share them with others on their own computer

Seed or seeder - A computer with a complete copy of a BitTorrent file (For a BitTorrent download to operate at least one seed computer is required).

Swarm - A group of computers that send (upload) or receive (download) the same file simultaneously

.torrent - A pointer file that directs your computer to the downloadable file

Tracker - A server that manages the file transfer process in BitTorrent