The Invisible Internet Project (I2P) is a garlic routing using overlay network and darknet that allows applications to send messages to each other pseudonymously and securely. Uses include anonymous Web surfing, chatting, blogging and file transfers. The software that implements this layer is called an I2P router and a computer running I2P is called an I2P node.
License: Open Source
I2P is designed for anonymous peer-to-peer communication and supports hidden services, while Tor Browser is primarily focused on providing anonymous web browsing and access to .onion sites. Tor tends to be faster and more user-friendly, whereas I2P offers greater resistance to traffic analysis.