IBM Public License

IBM Public License
Author	IBM
Latest version	1.0
Publisher	IBM
Published	August 1999
SPDX identifier	IPL-1.0
Debian FSG compatible	Yes
FSF approved	Yes
OSI approved	Yes
GPL compatible	No
Copyleft	Yes
Linking from code with a different licence	Yes

The IBM Public License (IPL) is a free software / open-source software license written and sometimes used by IBM. It is approved by the Free Software Foundation (FSF) and described as a "open-source license" by the Open Source Initiative.

The IPL differs from the GNU General Public License (GPL), in that it places the liability on the publisher or distributor of the licensed software code. According to IBM, this is to facilitate commercial use of open-source software, without placing the contributor at a risk of liability.^{[citation needed]} Proponents of the IPL note a clearer definition of responsibility for software code than that of the GPL.

The IPL is incompatible with the GPL because it contains restrictions not included in the GPL. According to the FSF "This is a free software license. Unfortunately, it has a choice of law clause which makes it incompatible with the GNU GPL.)"^[2]

The IPL differs from the GPL in the handling of patents, as IPL terminates the license upon patent disputes.

This license has also been criticised^{[by whom?]} because of provisions in section 4 which require commercial distributors of code covered by this license to indemnify all "upstream" originators for legal costs relating to lawsuits brought about of users of the software. It has been argued^{[by whom?]} that this exposes small distributors (e.g. Linux distributions that happen to sell CDs) to unbounded legal costs, possibly arising from vexatious claims.

Examples of software projects licensed under the IPL include Postfix, OpenAFS, and the now-unmaintained Jikes compiler for Java.