Apache License

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Apache License
ASF Logo.svg
The Apache Software Foundation logo
Author The Apache Software Foundation
Latest version2.0
Publisher The Apache Software Foundation
PublishedJanuary 2004;19 years ago (2004-01)
SPDX identifierApache-2.0
Debian FSG compatible Yes [1]
FSF approved Yes [2]
OSI approved Yes [3]
GPL compatible Only version 2.0 is compatible with only GPLv3. [2]
Copyleft No
Linking from code with a different licence Yes
Website www.apache.org/licenses

The Apache License is a permissive free software license written by the Apache Software Foundation (ASF). [4] It allows users to use the software for any purpose, to distribute it, to modify it, and to distribute modified versions of the software under the terms of the license, without concern for royalties. The ASF and its projects release their software products under the Apache License. The license is also used by many non-ASF projects.



Beginning in 1995, the Apache Group (later the Apache Software Foundation) released successive versions of the Apache HTTP Server. Its initial license was essentially the same as the original 4-clause BSD license, with only the names of the organizations changed, and with an additional clause forbidding derivative works from bearing the Apache name.

In July 1999, the Berkeley Software Distribution accepted the argument put to it by the Free Software Foundation and retired their advertising clause (clause 3) to form the new 3-clause BSD license. In 2000, Apache did likewise and created the Apache License 1.1, in which derived products are no longer required to include attribution in their advertising materials, only in their documentation. Individual packages licensed under the 1.1 version may have used different wording due to varying requirements for attribution or mark identification, but the binding terms were the same.

In January 2004, ASF decided to depart from the BSD model and produced the Apache License 2.0. The stated goals of the license included making it easier for non-ASF projects to use, improving compatibility with GPL-based software, allowing the license to be included by reference instead of listed in every file, clarifying the license on contributions, and requiring a patent license on contributions that necessarily infringe a contributor's own patents. [5] This license requires preservation of the copyright notice and disclaimer.

Licensing conditions

The Apache License is permissive; unlike copyleft licenses, it does not require a derivative work of the software, or modifications to the original, to be distributed using the same license. It still requires application of the same license to all unmodified parts. In every licensed file, original copyright, patent, trademark, and attribution notices must be preserved (excluding notices that do not pertain to any part of the derivative works). In every licensed file changed, a notification must be added stating that changes have been made to that file.

If a NOTICE text file is included as part of the distribution of the original work, then derivative works must include a readable copy of these notices within a NOTICE text file distributed as part of the derivative works, within the source form or documentation, or within a display generated by the derivative works (wherever such third-party notices normally appear).

The contents of the NOTICE file do not modify the license, as they are for informational purposes only, and adding more attribution notices as addenda to the NOTICE text is permissible, provided that these notices cannot be understood as modifying the license. Modifications may have appropriate copyright notices, and may provide different license terms for the modifications.

Unless explicitly stated otherwise, any contributions submitted by a licensee to a licensor will be under the terms of the license without any terms and conditions, but this does not preclude any separate agreements with the licensor regarding these contributions.

Apache License 2.0

The Apache License 2.0 attempts to forestall potential patent litigation in Section 3. The user is granted a patent license from each contributor to "make, have made, use, offer to sell, sell, import, and otherwise transfer the Work." Through an in terrorem clause, if the user sues anyone alleging that the software or a contribution within it constitutes patent infringement, any such patent licenses for that work are terminated.


The Apache Software Foundation and the Free Software Foundation agree that the Apache License 2.0 is a free software license, compatible with the GNU General Public License (GPL) version 3, [2] meaning that code under GPLv3 and Apache License 2.0 can be combined, as long as the resulting software is licensed under the GPLv3. [6]

The Free Software Foundation considers all versions of the Apache License to be incompatible with the previous GPL versions 1 and 2. [2] Furthermore, it considers Apache License versions before 2.0 incompatible with GPLv3. Because of version 2.0's patent license requirements, the Free Software Foundation recommends it over other non-copyleft licenses. [7] [2] If the Apache License with the LLVM exception is used, then it is compatible with GPLv2. [8]

Reception and adoption

In October 2012, 8,708 projects located at SourceForge.net were available under the terms of the Apache License. [9] In a blog post from May 2008, Google mentioned that over 25% of the nearly 100,000 projects then hosted on Google Code were using the Apache License, [10] including the Android operating system. [11]

As of 2015, according to Black Duck Software [12] and GitHub, [13] the Apache license is the third most popular license in the FOSS domain after MIT License and GPLv2.

The OpenBSD project does not consider the Apache License 2.0 to be an acceptable free license because of its patent provisions. The OpenBSD policy believes that when the license forces one to give up a legal right that one otherwise has, that license is no longer free. Moreover, the project objects to involving contract law with copyright law, stating "...Copyright law is somewhat standardized by international agreements, contract law differs wildly among jurisdictions. So what the license means in different jurisdictions may vary and is hard to predict." [14]

See also

Related Research Articles

The MIT License is a permissive free software license originating at the Massachusetts Institute of Technology (MIT) in the late 1980s. As a permissive license, it puts only very limited restriction on reuse and has, therefore, high license compatibility.

<span class="mw-page-title-main">Open-source license</span> Software license allowing source code to be used, modified, and shared

Open-source licenses facilitate free and open-source software (FOSS) development. Intellectual property (IP) laws restrict the modification and sharing of creative works. Free and open-source software licenses use these existing legal structures for the inverse purpose of granting freedoms that promote sharing and collaboration. They grant the recipient the rights to use the software, examine the source code, modify it, and distribute the modifications. These licenses target computer software where source code can be necessary to create modifications. They also cover situations where there is no difference between the source code and the executable program distributed to end users. Open-source licenses can cover hardware, infrastructure, drinks, books, and music.

Viral license is an alternative name for copyleft licenses, especially the GPL, that allows derivative works only when permissions are preserved in modified versions of the work. Copyleft licenses include several common open-source and free content licenses, such as the GNU General Public License (GPL) and the Creative Commons Attribution-ShareAlike license.

The Academic Free License (AFL) is a permissive free software license written in 2002 by Lawrence E. Rosen, a former general counsel of the Open Source Initiative (OSI).

The Open Software License (OSL) is a software license created by Lawrence Rosen. The Open Source Initiative (OSI) has certified it as an open-source license, but the Debian project judged version 1.1 to be incompatible with the DFSG. The OSL is a copyleft license, with a termination clause triggered by filing a lawsuit alleging patent infringement.

The Mozilla Public License (MPL) is a free and open-source weak copyleft license for most Mozilla Foundation software such as Firefox and Thunderbird. The MPL license is developed and maintained by Mozilla, which seeks to balance the concerns of both open-source and proprietary developers; it is distinguished from others as a middle ground between the permissive software BSD-style licenses and the General Public License. So under the terms of the MPL, it allows the integration of MPL-licensed code into proprietary codebases, but only on condition those components remain accessible.

The Common Development and Distribution License (CDDL) is a free and open-source software license, produced by Sun Microsystems, based on the Mozilla Public License (MPL). Files licensed under the CDDL can be combined with files licensed under other licenses, whether open source or proprietary. In 2005 the Open Source Initiative approved the license. The Free Software Foundation (FSF) considers it a free software license, but one which is incompatible with the GNU General Public License (GPL).

A permissive software license, sometimes also called BSD-like or BSD-style license, is a free-software license which instead of copyleft protections, carries only minimal restrictions on how the software can be used, modified, and redistributed, usually including a warranty disclaimer. Examples include the GNU All-permissive License, MIT License, BSD licenses, Apple Public Source License and Apache license. As of 2016, the most popular free-software license is the permissive MIT license.

<span class="mw-page-title-main">Eclipse Public License</span> Free software license similar to the Common Public License

The Eclipse Public License (EPL) is a free and open source software license most notably used for the Eclipse IDE and other projects by the Eclipse Foundation. It replaces the Common Public License (CPL) and removes certain terms relating to litigations related to patents.

This comparison only covers software licenses which have a linked Wikipedia article for details and which are approved by at least one of the following expert groups: the Free Software Foundation, the Open Source Initiative, the Debian Project and the Fedora Project. For a list of licenses not specifically intended for software, see List of free-content licences.

The Educational Community License (ECL) is a free and open source license based on the Apache license and created with the specific needs of the academic community in mind.

<span class="mw-page-title-main">Public-domain software</span> Software in the public domain

Public-domain software is software that has been placed in the public domain, in other words, software for which there is absolutely no ownership such as copyright, trademark, or patent. Software in the public domain can be modified, distributed, or sold even without any attribution by anyone; this is unlike the common case of software under exclusive copyright, where licenses grant limited usage rights.

<span class="mw-page-title-main">Public-domain-equivalent license</span> License that waives all copyright

Public-domain-equivalent license are licenses that grant public-domain-like rights and/or act as waivers. They are used to make copyrighted works usable by anyone without conditions, while avoiding the complexities of attribution or license compatibility that occur with other licenses.

License proliferation is the phenomenon of an abundance of already existing and the continued creation of new software licenses for software and software packages in the FOSS ecosystem. License proliferation affects the whole FOSS ecosystem negatively by the burden of increasingly complex license selection, license interaction, and license compatibility considerations.

License compatibility is a legal framework that allows for pieces of software with different software licenses to be distributed together. The need for such a framework arises because the different licenses can contain contradictory requirements, rendering it impossible to legally combine source code from separately-licensed software in order to create and publish a new program. Proprietary licenses are generally program-specific and incompatible; authors must negotiate to combine code. Copyleft licenses are commonly deliberately incompatible with proprietary licenses, in order to prevent copyleft software from being re-licensed under a proprietary license, turning it into proprietary software. Many copyleft licenses explicitly allow relicensing under some other copyleft licenses. Permissive licenses are compatible with everything, including proprietary licenses; there is thus no guarantee that all derived works will remain under a permissive license.

<span class="mw-page-title-main">Free-software license</span> License allowing software modification and redistribution

A free-software license is a notice that grants the recipient of a piece of software extensive rights to modify and redistribute that software. These actions are usually prohibited by copyright law, but the rights-holder of a piece of software can remove these restrictions by accompanying the software with a software license which grants the recipient these rights. Software using such a license is free software as conferred by the copyright holder. Free-software licenses are applied to software in source code and also binary object-code form, as the copyright law recognizes both forms.

BSD licenses are a family of permissive free software licenses, imposing minimal restrictions on the use and distribution of covered software. This is in contrast to copyleft licenses, which have share-alike requirements. The original BSD license was used for its namesake, the Berkeley Software Distribution (BSD), a Unix-like operating system. The original version has since been revised, and its descendants are referred to as modified BSD licenses.

<span class="mw-page-title-main">Copyleft</span> Practice of mandating free use in all derivatives of a work

Copyleft is the legal technique of granting certain freedoms over copies of copyrighted works with the requirement that the same rights be preserved in derivative works. In this sense, freedoms refers to the use of the work for any purpose, and the ability to modify, copy, share, and redistribute the work, with or without a fee. Licenses which implement copyleft can be used to maintain copyright conditions for works ranging from computer software, to documents, art, scientific discoveries and even certain patents.

<span class="mw-page-title-main">GNU General Public License</span> Series of free software licenses

The GNU General Public License is a series of widely used free software licenses that guarantee end users the four freedoms to run, study, share, and modify the software. The license was the first copyleft for general use and was originally written by the founder of the Free Software Foundation (FSF), Richard Stallman, for the GNU Project. The license grants the recipients of a computer program the rights of the Free Software Definition. These GPL series are all copyleft licenses, which means that any derivative work must be distributed under the same or equivalent license terms. It is more restrictive than the Lesser General Public License and even further distinct from the more widely used permissive software licenses BSD, MIT, and Apache.

Software relicensing is applied in open-source software development when software licenses of software modules are incompatible and are required to be compatible for a greater combined work. Licenses applied to software as copyrightable works, in source code as binary form, can contain contradictory clauses. These requirements can make it impossible to combine source code or content of several software works to create a new combined one.


  1. "The Apache Software License (ASL)". The Big DFSG-compatible Licenses. Debian Project . Retrieved 6 July 2009.
  2. 1 2 3 4 5 "Apache License, Version 2.0". Various Licenses and Comments about Them. Free Software Foundation. Archived from the original on 16 July 2009. Retrieved 6 July 2009.
  3. "OSI-approved licenses by name David Gutierrez & David Louie Gutierrez". Open Source Initiative. Archived from the original on 28 April 2011. Retrieved 31 March 2011.
  4. New Media Rights (12 September 2008). "Open Source Licensing Guide". California Western School of Law . Retrieved 28 November 2015. The 'BSD-like' licenses such as the BSD, MIT, and Apache licenses are extremely permissive, requiring little more than attributing the original portions of the licensed code to the original developers in your own code and/or documentation.
  5. "Apache License, Version 2.0". Apache Software Foundation. Retrieved 15 July 2019.
  6. Apache Software Foundation. "Apache License v2.0 and GPL Compatibility". Archived from the original on 15 January 2008. Retrieved 30 January 2008.
  7. "How to choose a license for your own work". gnu.org. Free Software Foundation. 15 December 2018. Retrieved 25 August 2019.
  8. "LLVM Exception | Software Package Data Exchange (SPDX)". spdx.org. Retrieved 22 June 2022.
  9. "Projects at SourceForge under Apache License" . Retrieved 28 October 2012.
  10. Stein, Greg (28 May 2008). "Standing Against License Proliferation". Google Open Source Blog.
  11. "Licenses". Android Open Source Project. Retrieved 25 August 2019.
  12. "Top 20 licenses". Black Duck Software. 19 November 2015. Archived from the original on 19 July 2016. Retrieved 19 November 2015.
  13. Balter, Ben (9 March 2015). "Open source license usage on GitHub.com". GitHub .
  14. "OpenBSD copyright policy". openbsd.org. OpenBSD Project. 28 May 2019.