You've probably used it. You almost certainly don't know what happened under the hood.
The Problem With One Server
Imagine a band releases their debut album for free. By morning, a million people are trying to download it. Their server buckles, downloads crawl, and the hosting bill becomes a catastrophe.
This is what the internet looked like before BitTorrent. If you wanted to distribute a large file, you needed powerful, expensive servers. The bigger your audience, the more it cost you. Popularity was a punishment.
BitTorrent looked at this problem and asked a different question entirely.
What If the Downloaders Were Also the Distributors?
That one idea is the whole thing.
When you download a file using BitTorrent, you simultaneously upload pieces of it to others who need them. The more people downloading, the faster everyone downloads. Popularity becomes a feature, not a problem.
The file is split into thousands of small pieces pulled from different people at the same time, then reassembled into the complete file. This is a peer-to-peer network — no single server in charge, everyone both a customer and a supplier.
Step 1: The Torrent File (or Magnet Link)
A .torrent file is not the content itself — it's a map describing the content: the file name, its size, how many pieces it's split into, a checksum fingerprint for each piece, and where to find people who have it. It doesn't contain the treasure. It tells you where to look and how to verify you found the real thing.
Magnet links do the same job with just a string of text — no file needed at all.
Step 2: The Tracker
Your client contacts a tracker — a server that keeps a list of everyone downloading or sharing a torrent. The tracker doesn't have the file. It's a matchmaker. You give it your address, it gives you a list of peers. It also registers you so future downloaders can find you.
Step 3: Talking to Peers
Your client connects to peers and they exchange piece lists. Your client is smart about this — it deliberately requests the rarest pieces first, ensuring scarce pieces spread through the network before someone goes offline.
You talk to many peers simultaneously, constantly dropping slow ones and finding faster ones. The full collection of everyone sharing a torrent is called the swarm.
Step 4: Pieces and Checksums
As pieces arrive, each one is verified against its checksum. The client runs a mathematical function on the received data and compares the result to what the torrent file says it should be. A match means the piece is genuine. A mismatch means it's silently discarded and requested again. You cannot be fooled into saving corrupted data.
Step 5: Seeding
Once your download completes, keeping your client open means you're now uploading pieces to others — this is called seeding. The system depends on it. If everyone stopped the moment they finished, the swarm would collapse.
BitTorrent even has a tit-for-tat mechanism: peers who upload more get faster downloads in return. Generosity is rewarded. Freeloading is punished. It's elegant social engineering baked directly into the protocol.
The Beautiful Part: What Happens Without a Tracker?
Trackers are a single point of failure. If one goes down, new peers can't find each other.
So the question became: what if we didn't need a tracker at all?
The answer is a DHT — Distributed Hash Table. Instead of one central directory, knowledge of who has what is spread across thousands of regular users' computers. Your client doesn't ask one server — it asks the network itself, hopping from node to node, each one pointing slightly closer to the answer.
The result: no single entity can be shut down, taken offline, or pressured. The network is the server. It lives as long as people participate. This is not just engineering — it's a philosophy. Information can be free not because someone decided it should be, but because the architecture makes it structurally true.
Why This Matters Beyond Piracy
BitTorrent's ideas are everywhere: Linux distributions ship via torrent, IPFS is built on the same principles, blockchain networks use peer-to-peer distribution, and game studios use it for update delivery. The insight that receivers can be distributors turned out to be one of the most durable ideas in networking.
Decentralization Didn't Stop at File Sharing
BitTorrent proved something the industry hadn't accepted: you don't need a server to build a reliable system. You need a protocol smart enough to turn participants into infrastructure.
Today we call this serverless computing — functions distributed across hundreds of edge locations with no single machine in charge. Amazon Lambda, Cloudflare Workers, Vercel Edge Functions are, at their philosophical core, children of the same thinking. The server is no longer a place. It's a role, and any node in the network can play it. Systems become faster, cheaper, and harder to destroy — because there is no single throat to choke.
Blockchain: BitTorrent's Philosophical Child
If BitTorrent decentralized file distribution, blockchain decentralized something far more ambitious — truth itself.
The connection is architectural, not metaphorical. A blockchain is a ledger held simultaneously by thousands of computers. When a transaction happens, nodes reach agreement through consensus — a mathematical vote — before writing it permanently. No single node can alter the record because it lives everywhere at once.
The integrity mechanism mirrors BitTorrent's checksums directly. Every block contains a cryptographic fingerprint of the block before it. Change anything and every fingerprint after it breaks — the tampering becomes mathematically obvious to every node in the network.
Bitcoin, Ethereum, every chain that followed — all fundamentally peer-to-peer networks with a shared ledger instead of a shared file. Satoshi Nakamoto described Bitcoin explicitly as a peer-to-peer electronic cash system. The lineage from BitTorrent is direct.
The Future Belongs to the Network
Here's the uncomfortable truth: you don't control your data. Your messages, photos, and identity live on servers owned by corporations who can suspend or sell your presence at any moment. Centralization was the price of convenience when most people couldn't run their own server.
That tradeoff is becoming harder to justify.
The next generation of the web is an attempt to rebuild core infrastructure on peer-to-peer principles — cryptographic identities no company controls, files stored on networks where you hold the keys, transactions validated by the network rather than a bank. This is what decentralization actually promises: the right to participate without asking permission from an owner, because there is no owner.
BitTorrent was the first large-scale proof this was possible — not theoretically, but in practice, at scale, used by millions of ordinary people who had no idea they were participating in one of the most resilient distributed systems ever built. Everything that followed is the same idea applied to larger domains.
The architecture is the guarantee. Not a promise, not a policy — the structure of the network itself.
We are still very early.
I'm Building One
emrent started with a simple obsession: I wanted to understand BitTorrent from the inside. Not use it — understand it. The only way I know how to do that is to build it. It is not a production client. It will not replace qBittorrent.
What it is — is PoC. Proof that the protocol is understandable, that the concepts in this article are not magic.
Architecturally, emrent is organized as a Cargo workspace — a collection of focused crates each responsible for one layer of the protocol: tracker communication over both HTTP and UDP, the peer handshake and wire protocol, piece selection and download logic, checksum verification, and finally disk I/O. On top of that sits a desktop interface built with Tauri and React, making it a fully usable application, not just a library.
If you're curious about how any of this translates into code, take a look at the repo: github.com/emrent-rs/emrent
Thanks for reading. If something was unclear or you want to go deeper on any section, find me on linkedin or my github account: github or by email: sospeterkinyanjui57@gmail.com
until next time, peace, focus
