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 Général 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 sequencer environment. Looping compositions are also supported.
* 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
* Stream to disk recording, allows all audio played from OpenSebJ to be saved
* A pitch shift roller, allows for pre-setup audio frequency's to be used in succession each time an audio sample is triggered
* Sample play positions on the multi track sequencer can be recorded to there exact position when triggered in the lay down window
* Scratch interface allows virtual needle movement directly over the wave form