.bit is a top-level domain that was created outside the most commonly used Domain Name System (DNS) of the Internet, and is not sanctioned by the Internet Corporation for Assigned Names and Numbers (ICANN).
The .bit domain is served via the cryptocurrency Namecoin infrastructure, which acts as an alternative, decentralized domain name system. Use of the .bit domain requires a copy of the Namecoin blockchain, a supporting public DNS server, or a web browser plug-in.
In February 2014, a beta version of a Windows/Linux Firefox plug-in called FreeSpeechMe was released that allows automated resolution of .bit addresses, by downloading the Namecoin block chain and running it in the background.
OpenNIC's DNS servers also support resolution of .bit domains.