The exciting code is distributed under the terms of the GNU General Public License.

exciting is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

exciting is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

Other Licenses

The code is packaged with libraries that are distributed under different licenses then the GPL. They are:

FoX XML library (BSD like license)
http://www.uszla.me.uk/FoX/DoX/Licensing.html

BLAS LAPACK
http://www.netlib.org/lapack/LICENSE

ARPACK
http://www.caam.rice.edu/software/ARPACK/RiceBSD.txt#LICENSE