KIM Licensing

Knowledgebase of Interatomic Models (KIM) Policy on Standards and Software Licensing.

This document describes the KIM policy on licensing and its rationale.

Policy Version: 3.0 (previous versions: v2.0) Date: May 26, 2021 POLICY: 0) All copyrightable Standards and any associated Software Implementations of those standards developed by the KIM organization will henceforth be licensed under the GNU Lesser General Public License v2.1 or later (LGPL-2.1-or-later). 1) All copyrightable works uploaded to must be licensed under one of the following categories: 1.0) Preferred Licenses: KIM highly recommends the following licenses: 1.0.0) GNU Lesser General Public License v2.1 or later (LGPL-2.1-or-later). See This is a GPL-compatible reciprocal license. 1.0.1) Apache License 2.0 (Apache-2.0) See This is a GPL-compatible academic license. (Note: This license is not compatible with GPL-2.0-only.) 1.0.2) Public Domain content U.S. government publications and other works that are in the public domain. 1.1) Other Licenses: KIM accepts content under any license that allows for redistribution, but prefers the licenses listed in Section 1.0 of this policy document. All uploaded content must be accompanied by its license and an associated valid SPDX License Expression unambiguously identifying the content license(s). See for more on the SPDX standards. 2) Modification to this policy may be made in accordance with established KIM by-laws and must be approved by the KIM Board in consultation with the KIM Director, KIM Technical Lead, and KIM Editor. RATIONALE FOR THE POLICY: The KIM project is based on the ideal that Science advances most efficiently when conducted in an open and forthcoming manner. This ensures that research results can be verified by independent scientists through replication of experiments and procedures --- a fundamental step in the process of establishing "accepted fact." In the context of KIM and, more generally, the field of atomistic simulation, this means that computer code must be readily available to all researchers. This consideration has led KIM to recommend Open Source licenses (as defined by the Open Source Initiative: for all copyrightable code in its system. In recent years a compelling argument for GPL Compatibility has emerged within the open source community, and the KIM project has decided to adopt this approach as represented by the above policy. This is a change from our previous "openness and collaboration" stance described in the KIM Licensing v2.0 policy. The decision to recommend LGPL-2.1-or-later, as opposed to LGPL-3.0-or-later, is primarily based on the fact that LAMMPS is distributed under GPL-2.0-only.