Thank you for your interest in Apache!

See the following links; 2.0 is the current version while 1.1 and 1.0 are older versions that the ASF no longer use:

• Apache License 2.0: http://www.apache.org/licenses/LICENSE-2.0.txt
• Apache Software License 1.1: http://www.apache.org/licenses/LICENSE-1.1.txt
• Apache Software License 1.0: http://www.apache.org/licenses/LICENSE-1.0.txt

Describing legal documents in non-legalese is fraught with potential for misinterpretation. Notwithstanding the text that follows, the actual text of the license itself is legally binding and authoritative.

That said, here's what the Apache license says in layman's terms:

It allows you to:

• freely download and use Apache software, in whole or in part, for personal, company internal, or commercial purposes;
• use Apache software in packages or distributions that you create.

It forbids you to:

• redistribute any piece of Apache-originated software without proper attribution;
• use any marks owned by The Apache Software Foundation in any way that might state or imply that the Foundation endorses your distribution;
• use any marks owned by The Apache Software Foundation in any way that might state or imply that you created the Apache software in question.

It requires you to:

• include a copy of the license in any redistribution you may make that includes Apache software;
• provide clear attribution to The Apache Software Foundation for any distributions that include Apache software.

It does not require you to:

• include the source of the Apache software itself, or of any modifications you may have made to it, in any redistribution you may assemble that includes it;
• submit changes that you make to the software back to the Apache Software Foundation (though such feedback is encouraged).

It depends entirely on which versions of our software you are talking about - you should adhere to the version of our license that covered the software in question. It should be exceedingly rare to come across version 1.0, and all active products should have had a version released under the Apache License 2.0. Feel free to contact the relevant project if you are unable to find an AL 2.0 version of their software.

While the core Apache developed code will be under one of the Apache licenses, other third party works may have been included and their license text may have been added to the Apache projects' LICENSE or NOTICE files. Alternatively, they may be available separately.

'Apache', 'Apache Software Foundation', the multicoloured feather, and the various Apache project names and logos are trademarks of The Apache Software Foundation, and are usable by others only with express permission from the ASF. Please see our Trademark Policy for more details.

Yes. All software developed by all projects of The Apache Software Foundation is freely available without charge from the Foundation's Web sites. This is specified in the Foundation's Articles of Incorporation.

No. We do not distinguish between personal, internal, or commercial use of our software. Packaging and redistribution of any of it is subject to the terms of our license, however.

Please see the ASF Exports Classifications and Source Links page.

Certainly. Version 2.0 of the license was designed to be reusable, and often has been reused by parties other than the ASF.

Yes, you are allowed to use and modify them. You just can't hold the ASF legally responsible if these documents are not exactly what you intend them to be. We recommend that you obtain your own legal advice so you know exactly what you are getting yourself into.

Also, if you adopt these agreements for your purposes, you have to make sure that the phrase 'Apache Software Foundation' or any confusingly similar references or parts that specifically refer to the Apache organisation do not appear in your version of the agreements (except to note that your version is derived and differs from the original provided by the ASF).

Absolutely -- subject to the terms of the Apache license, of course. You can give your modified code away for free, or sell it, or keep it to yourself, or whatever you like. Just remember that the original code is still covered by the Apache license and you must comply with its terms. Even if you change every single line of the Apache code you're using, the result is still based on the Foundation's licensed code. You may distribute the result under a different license, but you need to acknowledge the use of the Foundation's software. To do otherwise would be stealing.

If you think your changes would be found useful by others, though, we do encourage you to submit them to the appropriate Apache project for possible inclusion.

In a word, no. You may, however, use phrasing such as 'based on Apache', 'powered by Apache', or 'based on Apache technology'. You must not use the Foundation's marks in any way that states or implies, or can be interpreted as stating or implying, that the final product is endorsed or created by the Apache Software Foundation. For example, it would be acceptable to use a name like 'SuperWonderServer powered by Apache', but never a name like 'Apache SuperWonderServer'. This is similar to the distinction between a product named 'Microsoft Burp' and 'Burp for Microsoft Windows'.

You may similarly identify the specific Foundation project whose code you're using, such as with 'based on Apache Xerces' or 'powered by Apache Tomcat technology'.

If you wish to use a name including any of the Foundation's marks, such as the word 'Apache', it's best to ask our permission first. Please see our Trademark Policy for more details.

No. You can keep your changes a secret if you like. Maybe your modifications are embarrassing, maybe you'll get rich selling those improvements. Whatever. But please seriously consider giving your changes back! We all benefit when you do.

Yes, you may translate the license text into your local language. However, any such translated text is only for the convenience of understanding, and is not legally binding. Only the English-language version of the license, which you must continue to include in your packaging, is authoritative and applicable in case legal interpretation is required.

From the Free Software Foundation website:

Apache License, Version 2.0

This is a free software license, compatible with version 3 of the GPL. Please note that this license is not compatible with GPL version 2, because it has some requirements that are not in the older version. These include certain patent termination and indemnification provisions.

This is a four part question:

Q1:

If I own a patent and contribute to a Work, and, at the time my contribution is included in that Work, none of my patent's claims are subject to Apache's Grant of Patent License, is there a way any of those claims would later become subject to the Grant of Patent License solely due to subsequent contributions by other parties who are not licensees of that patent.

A1:

No.

Q2:

If at any time after my contribution, I am able to license other patent claims that would have been subject to Apache's Grant of Patent License if they were licenseable by me at the time of my contribution, do those other claims become subject to the Grant of Patent License?

A2:

Yes.

Q3:

If I own or control a licensable patent and contribute code to a specific Apache product, which of my patent claims are subject to Apache's Grant of Patent License?

A3:

The only patent claims that are licensed to the ASF are those you own or have the right to license that read on your contribution or on the combination of your contribution with the specific Apache product to which you contributed as it existed at the time of your contribution. No additional patent claims become licensed as a result of subsequent combinations of your contribution with any other software. Note, however, that licensable patent claims include those that you acquire in the future, as long as they read on your original contribution as made at the original time. Once a patent claim is subject to Apache's Grant of Patent License, it is licensed under the terms of that Grant to the ASF and to recipients of any software distributed by the ASF for any Apache software product whatsoever.

Q4:

What is an Apache product?

Q3:

An Apache product is a body of software being developed by the ASF that the ASF intends to both alter and to publish as a separate line of releases.