It is primarily available for Windows. Ensure you download the correct version (32-bit or 64-bit) that matches both your DAW and your operating system.
The genius of ReaStream lies in its VST implementation. By packaging itself as a VST plugin, it becomes compatible with any VST host, not just REAPER. A user can stream audio from Ableton Live to Logic Pro, from Pro Tools to FL Studio, or even from REAPER to a live coding environment like Pure Data. This cross-compatibility breaks down the "walled gardens" of DAW-specific networking protocols.
While ReaStream is built into REAPER, other DAW users must download the standalone ReaPlugs suite. YouTube·J. Behr How to stream your music with OBS using ReaStream