Yadex can build and edit levels for the alpha and beta versions of Doom, Doom, Doom II, Ultimate Doom, Final Doom and Heretic. There is also limited support for Hexen and Strife. The additional features of several source ports are also supported.
Yadex is released under the terms of the GNU General Public License.
Yadex has not been updated since about 2003, and it no longer compiles correctly with newer versions of the GNU C compiler, usually generating a segmentation fault. There is a fork of Yadex called Eureka that works correctly with newer versions of GCC.