Subsonic is a free audio streaming tool for Android, iOS and Windows Phone devices. It gives you access to music stored on your computer via a network or internet connection from many popular smartphones and tablets. The software is designed to support large music collections (up to hundreds of gigabytes) and provides the ability to stream audio to multiple users at the same time.

It is optimized for streaming MP3 files, but it can handle many other formats as well. Subsonic can also transmit video via HTTP protocol, and the installation of additional plug-ins extends the functionality of the program with on-the-fly conversion of streaming formats such as WMA, FLAC, APE, Musepack or WavPack. Subsonic has options to define the upper transfer rate limit of the streams and automatically adjust the bitrate values to the imposed limits.

The tool can be used for local media collection management, offering convenient search and indexing functions for large audio libraries. There was also a built-in support for podcasts broadcast over the Internet. The application was created in Java language, so it is available for all commonly used system platforms - Windows, Linux and Mac OS.

It is based on a web interface, which can be operated from any web browser, after entering the address http://localhost:4040. An appropriate client application should be installed on the device on which we would like to play the transmitted streams.