OpenSebJ is a free real time audio sample mixer that runs on Microsoft Windows operating systems. The source code for OpenSebJ is released under the GNU General Public License.

Some of OpenSebJ's features include:
* Supports loading of 255 Audio samples (wave format), which can be played in real time
* Sample properties such as, Volume, Pan and Frequency can be adjusted individually for each sample (even during mid play)
* A composition tool is provided, presented in a familiar multi-track window environment
* Samples can be linked to keys on the keyboard and trigged in real time when a key press occurs
* Each sample can also have the play cursor position adjusted while the sample is playing, to provide a virtual needle to be moved