Avahi implements Zeroconf Networking. It allows programs to discover services like printers on local networks without prior configuration. It also allows applications to set up services that are reachable through the local network without configuration; for example, a chat program that "finds" other chat users in a LAN without having to set up a central chat server first.

Avahi is an implementation of the DNS Service Discovery and Multicast DNS specifications, which are part of Zeroconf Networking.

Various programs in GNOME use Avahi to discover services. Gnome-user-share (a module for the Nautilus file manager) lets users of a local network to share files with each other, and it finds computers that are sharing files via Avahi. Vino, a remote-desktop viewer, uses Avahi to find remote desktop servers. PulseAudio, GNOME's low-level audio API, uses Avahi to make it possible to route sound through local networks.