What Is I2P? A Guide to How It Works and What It’s For

Most privacy tools protect your traffic as it moves through the regular Internet. The Invisible Internet Project (I2P) goes further: it builds a separate, fully encrypted network where users can communicate, browse, and host services without revealing their identity or location. It’s considered a part of the dark web.

This article explains how I2P works, how it differs from Tor and VPNs, and what kind of privacy and security it actually provides.

What Is I2P?

The Invisible Internet Project (I2P) is a decentralized peer-to-peer (P2P) network built to protect online communication. 

It runs on top of the regular internet but forms its own encrypted environment, a private network where users connect directly with each other, unlike the public web, which depends on large central servers owned by companies or governments.

This design makes it extremely difficult for anyone to trace who is communicating with whom or even to see that communication is happening at all.

Within this secure network, users can browse internal websites (called eepsites), exchange messages, share files, and host services while keeping their identities and location private.

How Does I2P Work?

I2P protects anonymity through layered encryption, decentralized routing, and a method called garlic routing.

Garlic routing combines several encrypted messages from the same sender into one larger packet. Each message inside, called a clove, can have its own destination or delivery instruction. This makes network traffic harder to analyze because observers can’t tell which parts belong to which exchange.

When you send data through I2P, the encrypted packet travels through a randomly selected path of volunteer computers, called nodes. Each node removes one layer of encryption, which is just enough to know where to send the message next, but never enough to learn who sent it or where it will end up.

To strengthen privacy further, I2P uses two separate one-way tunnels: one for sending and another for receiving. These tunnels are temporary and automatically rebuilt using different nodes, so even if someone could observe one route, they couldn’t link it to the full path or identify the people communicating.

Key Characteristics of I2P

• Decentralized network: I2P has no central servers. It runs on a global web of volunteer computers that forward encrypted data between users.
• Self-organizing: The network manages itself — routers automatically share information through a distributed database to stay connected without an admin or authority.
• Encrypted by default: Every message is wrapped in multiple layers of encryption, so no single node ever sees the full contents or both ends of a conversation.
• One-way traffic: Data always travels in one direction per tunnel, preventing anyone from seeing the full communication in one place.
• Constantly changing routes: Tunnels are temporary and automatically rebuilt, keeping routes unpredictable and difficult to trace.
• Anonymous services: I2P hosts anonymous sites called eepsites, which are only accessible inside the I2P network.
• Private addressing: Services inside I2P use temporary internal connection paths instead of public IP addresses, allowing others to reach them without revealing the host’s real location.

I2P Pros and Cons

I2P Pros

✅ Strong anonymity: I2P hides both identity and location by encrypting traffic and sending it through many different paths.
✅ Hard to censor: Because it runs on thousands of volunteer computers worldwide, blocking or shutting it down is very difficult.
✅ Private network: All activity stays inside I2P’s own network, which reduces the risk of outside monitoring.
✅ Secure communication: Supports encrypted email, messaging, and file-sharing within the network.
✅ Built for privacy: Hidden websites and services can operate without revealing their real addresses.

I2P Cons

⚠️ Not for the regular internet: I2P is its own network; it’s not meant for visiting normal websites.
⚠️ Smaller community: With fewer users, speeds and content availability can vary.
⚠️ Requires setup: Installing and configuring I2P takes more effort than most tools.
⚠️ Slower performance: Multi-layer encryption and routing through multiple peers make it slower than direct internet use.
⚠️ Niche software: It’s still a specialist tool, not widely supported by mainstream apps or services.

I2P Use Cases

In practice, I2P’s architecture supports a variety of real-world, privacy-focused applications:

• Private hosting: Run websites and online services that exist only inside the I2P network, protected from outside access.
• Secure communication: Exchange messages, emails, and files with end-to-end encryption and hidden IP addresses.
• Community platforms: Build forums, blogs, or shared repositories that operate within I2P for long-term privacy.
• Academic and technical research: Study anonymity networks, routing systems, or encryption methods in a real-world environment.
• Privacy-focused projects: Develop or test applications that rely on decentralized, anonymous infrastructure.

How an I2P Setup Works

To use I2P, you start by installing an I2P router, which is a lightweight program that connects your computer to the I2P network. The router is what actually runs the network: it builds encrypted tunnels, exchanges traffic with other users, and manages your connections in the background.

Once the router is running, you access it through a local dashboard called the Router Console. This lets you check your connection status, monitor peers, and manage privacy settings.

To browse within I2P, you don’t need a special browser, just a regular one configured to send traffic through I2P’s encrypted proxy. This setup is often referred to as the I2P browser, even though it’s really your own browser connected securely to the I2P network.

When everything’s set up, your router discovers peers and starts routing encrypted traffic through tunnels that refresh automatically. The result is a private, self-contained network where your activity stays hidden from the public internet.

Is I2P the Same as Tor?

Despite sharing some similarities, I2P isn’t the same as Tor (The Onion Router).

• I2P is a decentralized network designed for anonymous communication within its own system. 
• Tor is a network that anonymizes access to and from the public internet.

Let’s take a look at some of the major differences that set I2P and Tor apart.

Networking

Tor relies on directory authorities to help users find relays, making it a more centralized system than I2P’s fully distributed approach. I2P uses network management and statistics gathering tools to collect information that helps I2P maintain security, monitor network performance, and perform debugging when necessary. 

The downside is that a decentralized structure and reliance on outside tools can create vulnerabilities in the network. Tor’s more centralized network is designed to prevent the collection of most forms of network or statistical data, reducing the risk of exposing user information.

Routing 

Tor uses Onion routing, which anonymizes online communications by layering single messages and routing them through random volunteer-operated nodes. I2P uses a similar approach called garlic routing, which builds on the same idea but bundles multiple messages together for added efficiency and security. 

Garlic routing bundles (called bulbs) contain multiple messages – similar to data packets – known as cloves. Each message has delivery instructions, and the data is revealed once it reaches its destination. The multi-layered routing method enables the efficient routing of multiple messages rather than processing each message individually.

Load Balancing

Unlike Tor, which uses a few central servers to help manage connections, I2P has no central point of control. It spreads this responsibility across all the computers in its network, which means it can sometimes handle congestion more efficiently. Instead of sending data along one fixed path, I2P splits traffic across multiple routes and peers, helping to balance the load and keep the network fast and resilient.

Main Use

While Tor can access significant areas of the dark web, most people use it to add a layer of anonymity to their regular browsing and file-sharing. I2P, on the other hand, can only access eepsites, which are considered part of the dark web. 

Should You Use a VPN with I2P?

That depends. I2P is designed to provide privacy on its own. It routes traffic through multiple encrypted hops, so other users in the network never see your real IP address.

A VPN doesn’t change how I2P functions internally, but it can affect what others outside the network can see.

For example, internet service providers can detect I2P traffic patterns, even if they can’t read the content. When you use a VPN before connecting to I2P, the provider would only see an encrypted connection to the VPN, keeping your I2P connection private.

FAQ