zlib license
AuthorJean-loup Gailly and Mark Adler
Latest version1.2.11[1]
PublisherJean-loup Gailly and Mark Adler
Published15 April 1995
SPDX identifierZlib
Debian FSG compatibleYes
FSF approvedYes[2]
OSI approvedYes
GPL compatibleYes[2]
Linking from code with a different licenceYes

The zlib license is a permissive free software license which defines the terms under which the zlib software library can be distributed. It is also used by many other free software packages. The libpng library uses a similar license sometimes referred interchangeably as zlib/libpng license.

The zlib license has been approved by the Free Software Foundation (FSF) as a free software license,[2] and by the Open Source Initiative (OSI) as an open source license.[3] It is compatible with the GNU General Public License.[2]


The license only has the following points to be accounted for:

The license does not require source code to be made available if distributing binary code.


The license terms are as follows:

Copyright (c) <year> <copyright holders>

This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not
   claim that you wrote the original software. If you use this software
   in a product, an acknowledgment in the product documentation would be
   appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.

See also


  1. ^ "Zlib License".
  2. ^ a b c d "Various Licenses and Comments about Them". Retrieved 17 June 2007. License of ZLib [...] is a free software license, and compatible with the GPL.
  3. ^ "The zlib/libpng License (Zlib)". Retrieved 16 January 2013.