libp2p is a universal, cross-platform, multi-language, modular peer-to-peer networking library powering multiple large-scale networks, for example IPFS. In the first part of the talk we’ll present the basic building blocks of the library and explain how they fit together. In the second part, we’ll take a closer look at the recently added decentralized hole punching feature, allowing NAT and firewall traversal without the need for any central coordination servers (STUN and TURN).