Peer-to-peer (P2P) network

A peer-to-peer network is one in which computers connect directly to each other as equals, sharing data without a central server in the middle. File-sharing systems such as BitTorrent made the idea famous; Bitcoin applied it to money and described itself in its white paper as "a peer-to-peer electronic cash system".

On Bitcoin and other blockchains, each node connects to a handful of peers and passes on new transactions and blocks it hears about, so information spreads across the whole network within seconds. Because there is no central server, there is no single point that can be switched off, and anyone can join by running the software.

The phrase is also used for P2P trading, where two people swap crypto for money directly, often using an exchange as an escrow service. That is related but different: P2P trading describes how a trade is arranged, whereas a P2P network describes how the underlying computers communicate.