License Zero

gainful open software development

September 11, 2019

Parity 7.0.0-pre.1 cleaner, clearer, and easier to read

The License Zero Reciprocal Public License, which became Parity, was the first public software license to meet my personal standards of brevity and readability. Since then, more have followed, including the Blue Oak Model License, Polyform Project licenses, the latest draft of the Cryptographic Autonomy License, and my own API Copyleft License.

Each of those licenses took at least partial inspiration from Parity’s style. Each of those licenses has put more eyeballs—lawyers’ and hackers’—on the rudiments of public software licensing since. In version 7.0.0, Parity will take a few lessons from the licenses it inspired.

The first preview of Parity 7.0.0 follows. It’s a bit longer than Parity 6.0.0, but also much easier to read. Have a read for yourself.

This new work would not have happened, or been possible, without the interest and support of many new users. Special thanks are due to Kat Marchán, Markus Binsteiner, Daniel Compton, Casey Kuhlman, and Han Seoul-Oh. I’m sure I’m forgetting others.

Development continues. Please feel free to send issues and pull requests to the GitHub repository, which is more active today than it’s ever been before.

The Parity Public License 7.0.0-pre.1

Contributor: [name]

Source Code: [source]


This license lets you use and share this software for free, as long as you contribute software you make with it, other than prototypes.


In order to receive this license, you must agree to its rules. The rules of this license are both obligations under that agreement and conditions to your license. You must not do anything with this software that triggers a rule that you cannot or will not follow.

The contributor licenses you to do everything with this software that would otherwise infringe their copyright in it.


You must ensure that everyone who gets a copy of any part of this software from you, with or without changes, also gets the text of this license and the contributor and source code lines above.


The contributor licenses you to do everything with this software that would otherwise infringe any patent claims they can license or become able to license.


Do not make any legal claim against anyone accusing this software, with or without changes, alone or with other software, of infringing any patent claim.


The contributor cannot revoke this license.


With the exception of prototypes:

  1. Contribute all changes and additions you make to this software

  2. If you combine this software with other software, contribute that software.

  3. Contribute other software you develop, deploy, monitor, or run with this software.

  4. When in doubt, contribute.


You need not contribute prototype changes, additions, or other software that you do not end up using for more than thirty calendar days, sharing outside the development team working on the prototype, or using to provide a service to anyone else.


When this license requires you to contribute:

  1. Publish all source code, in the preferred form for making changes, through a freely accessible distribution system widely used for similar source code, so the contributors and others can find and copy it.

  2. Ensure that each part of that source code is available to the public under a license at least as permissive as this one, such as MIT, two-clause BSD license, Apache 2.0, Charity 3.0.0, or Blue Oak Model 1.0.0.

  3. Take these steps within thirty calendar days of when you first did anything requiring contribution.

Note that this license does not allow you to change the license terms for this software, but only to contribute software covered by Copyleft under qualifying licenses.


You are excused for unknowingly breaking Copyleft if you contribute as required, or stop doing anything requiring this license, within thirty days of learning you broke the rule.

No Liability

As far as the law allows, this software comes as is, without any warranty or condition, and the contributor will not be liable to anyone for any damages related to this software or this license, under any kind of legal claim.