Nx2 is a somewhat complex Web application that acts as a frontend to music databases. Based on XUL, it runs in Gecko based browsers such as Firefox. Built on this idea is a client/server model where several Nx2 frontends can connect to each other, creating a way to link together databases on different networks.
Nextls is a console application that keeps track of your music collection using a MySQL database to store information such as length, bitrate, metadata, and where on the hard drive it is located. When Nextls is launched, it will figure out any changes done since the previous run and update the database accordingly. The database is very simple to work with, and there also exists a sister project in Nx2 that will allow you to take your database online and stream your music from a Web browser.