Several projects have started using XCB.
- Xlib itself has replaced Xtrans with XCB for the low-level transport layer (see XlibXcb).
- The Cairo library has an experimental XCB backend.
- Vincent Torri has worked to port evas canvas component of Enlightenment from Xlib to XCB.
- The recent MPX (multi-pointer) extension was prototyped using XCB.
- Work is ongoing to port selected default X apps from Xlib and Xt to XCB.
- awesome, a window manager, uses XCB instead of Xlib.
- Compiz requires XCB.
- Xine and the Kaffeine KDE frontend for Xine use XCB, and XCB fixed some previously unfixable threading problems.
- VLC media player uses XCB
- samurai-x, a window manager written in python. samurai-x2 uses xcb instead of Xlib.
- Unagi, a composite manager using XCB.
In addition, there are a number of demos available from the XCB repository.