aria2 is a utility for downloading files. It has completely new design concept from its predecessor, Aria, and is written from scratch. aria2 has a segmented downloading engine in its core. It can download one file from multiple URLs or multiple connections from one URL. This results in very high speed downloading, much faster than ordinary browsers. This engine in was implemented in a single-thread model. The architecture is clean and easy to extend.

aria2 currently supports HTTP, FTP, and BitTorrent.