AllPeers is a free software extension for the Mozilla Firefox browser. The extension allows building a social network and sharing files on a P2P basis. It uses a darknet style of peer-to-peer communication; files and information shared between users are only accessible as long as the users have each other on their respective access lists - their 'trusted private network'. AllPeers beta version was launched on August 24, 2006, and is still currently in development. It works on Windows, Linux and Mac, which, once downloaded, becomes a toolbar in Mozilla Firefox.

AllPeers uses open source BitTorrent technology to facilitate file transfer. The extension does not require any ports be opened. AllPeers encrypts its communication using standard protocols like SSL so as to protect the user against 3rd party intervention listening in. AllPeers at the start its beta launch was 200,000 lines of C++ and JavaScript code.

Although the AllPeers client was open sourced in March 2007, the server source remains closed. AllPeers claims this is because the network must have a single, stable server instance to function reliably.