zlib license

Author	Jean-loup Gailly and Mark Adler
Latest version	1.2.11[1]
Publisher	Jean-loup Gailly and Mark Adler
Published	15 April 1995
SPDX identifier	Zlib
Debian FSG compatible	Yes
FSF approved	Yes[2]
OSI approved	Yes
GPL compatible	Yes[2]
Copyleft	No
Linking from code with a different licence	Yes

The zlib license is a permissive software license which defines the terms under which the zlib software library can be distributed. It is also used by many other open-source packages. The libpng library uses a similar license, libpng 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:

• Software is used on 'as-is' basis. Authors are not liable for any damages arising from its use.
• The distribution of a modified version of the software is subject to the following restrictions:
  1. The authorship of the original software must not be misrepresented,
  2. Altered source versions must not be misrepresented as being the original software, and
  3. The license notice must not be removed from source distributions.

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.

• Comparison of free and open-source software licenses
• Software using the zlib license (category)

• License text on the zlib homepage