aria2 is a free, open-source CLI download utility supporting HTTP, FTP, SFTP, BitTorrent, and Metalink with multi-connection, multi-source downloading.
aria2 is a free, open-source, cross-platform command-line download utility that supports HTTP, HTTPS, FTP, SFTP, BitTorrent, and Metalink protocols. It was created by Tatsuhiro Tsujikawa and first released in 2006, and has been maintained for roughly two decades since.
Unlike graphical download managers, aria2 is designed to be lightweight and scriptable, exposing an XML-RPC and JSON-RPC interface that lets it be controlled remotely, which is why it is commonly used as the download engine inside third-party web and mobile front ends.
aria2 is not a commercial product. It has no company or pricing behind it, and its source code is freely available for anyone to use, audit, or modify.
aria2's core strength is multi-protocol, multi-source, multi-connection downloading: it can pull a single file from HTTP, FTP, SFTP, and BitTorrent sources simultaneously, opening up to 16 parallel connections to maximize available bandwidth.
Its BitTorrent client includes DHT, peer exchange, encryption, magnet URI support, web seeding, selective downloads, local peer discovery, and UDP tracker support, giving it capability comparable to dedicated torrent clients.
It supports the Metalink format for file verification and multi-source aggregation, and uses very little memory, typically 4 to 9 MiB, making it well suited to embedded and resource-constrained environments like NAS devices and routers.
aria2 is completely free and open source. There are no paid tiers, subscriptions, or licensing costs; users can download, run, and modify it at no charge under its open-source license.
Yes, aria2 is completely free and open source with no paid tiers.
aria2 supports HTTP, HTTPS, FTP, SFTP, BitTorrent, and Metalink.
aria2 itself is a command-line tool; graphical interfaces are provided by third-party front ends and web UIs that control it via RPC.
aria2 was created by Tatsuhiro Tsujikawa and first released in 2006.
Its lightweight memory footprint and multi-protocol, multi-connection downloading make it well suited for embedded environments like NAS operating systems and router firmware.
Yes, aria2 can download a single file from HTTP/FTP and BitTorrent sources simultaneously and can seed downloaded data back into the BitTorrent swarm.
Yes, though official development has slowed in recent years, aria2 continues to receive updates, and community forks exist to address maintenance gaps.