How Fair Source Works

Any individual user can view, download, execute, and modify the code free of charge. Up to a certain number of users from an organization can use the code for free, too. After an organization hits that user limit, it will start paying a licensing fee determined by the software publisher.

Example: Alice releases FooApp as Fair Source 25, licensed under the Fair Source License with a user limit of 25. Bob can view and modify the code and run FooApp free of charge for personal use. Up to 25 people at Bob’s company can use the code and run FooApp free of charge for business purposes. When 26 or more people at Bob’s company are using or running the code, Bob’s company must pay Alice.

The Fair Source License can be applied to software applications and their source code. It is not currently suitable for library or plugin code.

Benefits of Fair Source

Fair Source License

Fair Source License, version 0.9

Copyright © [year] [copyright owner]

Licensor: [legal name of licensor]

Software: [name software and version if applicable]

Use Limitation: [number] users

License Grant. Licensor hereby grants to each recipient of the Software (“you”) a non-exclusive, non-transferable, royalty-free and fully-paid-up license, under all of the Licensor’s copyright and patent rights, to use, copy, distribute, prepare derivative works of, publicly perform and display the Software, subject to the Use Limitation and the conditions set forth below.

Use Limitation. The license granted above allows use by up to the number of users per entity set forth above (the “Use Limitation”). For determining the number of users, “you” includes all affiliates, meaning legal entities controlling, controlled by, or under common control with you. If you exceed the Use Limitation, your use is subject to payment of Licensor’s then-current list price for licenses.

Conditions. Redistribution in source code or other forms must include a copy of this license document to be provided in a reasonable manner. Any redistribution of the Software is only allowed subject to this license.

Trademarks. This license does not grant you any right in the trademarks, service marks, brand names or logos of Licensor.


Termination. If you violate the terms of this license, your rights will terminate automatically and will not be reinstated without the prior written consent of Licensor. Any such termination will not affect the right of others who may have received copies of the Software from you.


About the Fair Source License

How is the Fair Source License similar to (or different from) open-source licenses?

The Fair Source License is not an open-source license and doesn’t intend to be an open-source license. Fair Source allows usage, redistribution, and modification when the usage is below the Use Limitation. Once an organization exceeds the Use Limitation (which is determined by the licensor), it must pay a license fee to continue doing those things.

Why did you write a new license? Why didn’t you use GPL/MIT/BSD/Apache?

Open source licenses are excellent. They have helped advance technological progress, and we love them for that. However, open source doesn’t make sense for all code. If a company open sources code that represents its core business value, it would generally fail as a business—and it couldn’t continue to build great software for you.

By creating the Fair Source License, we’re offering the world a new choice in between open source and closed source. Fair Source enables companies to share source code with the public and still drive revenue. It’s the best of both worlds—transparency and progress without sacrificing our businesses.

What does the license name (“Fair Source 25,” “Fair Source 50,” etc.) mean?

We named it “Fair Source” because you get access to source code (like you do with open source), but it’s a fair approach to licensing for code creators who want to combine sharing their code with monetization. The “25” (or other number) in the name indicates the Use Limitation, which stipulates that users must pay for the licenses once they meet the given user threshold. If you use “Fair Source 25” licensed software, for example, your organization will be required to pay a licensing fee once you hit the 25-user limit.

In addition, we recommend specifying the version of the Fair Source License you wish to apply. For example, “Fair Source 25 (v0.9).”

How is the Fair Source License different from dual GPL/commercial licensing?

In a dual GPL/commercial licensing situation, companies pay for a commercial license to prevent the GPL from “infecting” their own code. To us, that approach is less transparent and harder to understand. Fair Source is short, simple and easy to understand. Like a dual-licensed product, you can try the software for free (up to the Use Limitation). You can redistribute the software, too—all without having to figure out complicated open-source terms.

How is the Fair Source License different from “shared source”?

“Shared source” referred to a model developed by Microsoft (and no longer used by Microsoft) that allowed its customers to receive source code for proprietary products to which the customers purchased binary licenses. The Fair Source License grants broader rights that apply to everyone, not just existing customers. Also, the Fair Source License explicitly allows modifications and redistribution, whereas shared source generally only permitted use of the code.

Using the Fair Source License

Can I use the Fair Source License for my own software?

Yes. We invite the entire coding community to adopt our simple, standardized, proprietary license. To use the Fair Source License on your own software, fill out the template available at Make sure to update the name of the owner of the copyright (i.e. you or your company), the year of the copyright notice, the name of your software, and the user limit.

Can I change the license?

Our license is very simple, so we don’t claim any copyright in the license text. If you do change the license text, please remove the name “Fair Source License” to make it clear that you are not using our specific license.

Can I use Fair Source software for myself or my friends and family?

Yes. As an individual, you can use the software all you want for your own personal use. The Use Limitation will only apply if you use the software for the benefit of a company.

Can I use Fair Source software inside my company?

Yes. You must pay a license fee if your organization has more people using the software than the specified Use Limitation. For example, let’s say the software is licensed as Fair Source 25 (i.e., the Use Limitation is 25 users). If less than 25 people use the software within your company, the software is free. If 25 or more people use the software, your company must pay a license fee to use the software.

What if the licensor decides to change the Use Limitation in the future?

The licensor may change the Use Limitation in the future, but you will always be able to use any Fair Source software under the least restrictive license offered for that software. For example, if we changed the limit to 50 users, we would refer to the “Fair Source 50 License” and users could benefit from this less restrictive limit. If we changed the limit to 20 users, we would refer to the “Fair Source 20 license” and users would still have the option to use the “Fair Source 50 license,” which is less restrictive. Just make sure the new limits apply to the software you are actually using—we may offer different products under different Use Limitations.

Can I use Fair Source code in a different open-source project?

No. Unlike open source, Fair Source has a Use Limitation built into the license. This means the Fair Source license will not be compatible with your project’s open source license.

Can I use Fair Source code in the code base for my commercial, closed-source product?

Probably not. If your proprietary license includes the Use Limitation, it might be compatible with the Fair Source license. However, we strongly discourage incorporating Fair Source licensed software into proprietary projects. Your customers would be better off using the software under our license so that you are not responsible for policing the Use Limitation.

If I modify the source code, can I redistribute my modified version under the MIT License?

No. Your modified version consists of the original software (which is under the Fair Source License) and your modifications, which together constitute a derivative work of the original software. The license does not grant you the right to redistribute under a license like MIT without the Use Limitation.

If I contribute a patch to your project, what license applies to the patch?

As with many types of licenses, a project under the Fair Source License will require contributors to sign Contributor License Agreements. These agreements grant rights to the project’s owner. Once the agreements are signed, any patches will be placed under the same license as the rest of the project. Many Contributor License Agreements will work with Fair Source. If you are asked to sign one, we advise you to review its terms carefully.

My Fair Source License terminated automatically. Can I fix the violation?

If you’ve made a mistake and violated the license, contact the licensor for a reinstatement. Please note that going over the Use Limitation is not a violation of the license and will not terminate your license, but it will mean you are obligated to pay fees for the additional use.

What if I want different license terms?

Contact the licensor. They may be able to partner with you to figure out what will work best for your company.

Understanding the Use Limitation

What counts as “using” Fair Source licensed software with respect to the Use Limitation (e.g., 25-user limit)?

The license doesn’t define “use” exactly because the way people deploy software changes all the time. Instead, it relies on a common-sense definition. For example, executing the software, modifying the code, or accessing a running copy of the software constitutes “use.” If your colleague runs the software on your local network and you access it from your web browser, that behavior would constitute “use.” Just viewing or downloading the software does not constitute “use.” You also are able change users on the license in a reasonable way (such as when one user leaves your company and another joins).

How will I know if my company exceeds the Use Limitation?

We recommend tracking the number of users who use the software internally, as you would for all other commercial software that charges per user. Products licensed under Fair Source may track and display usage data and alert the licensor if the Use Limitation is exceeded, but because you have the source code, the licensor can’t stop you from removing that functionality. We trust the software community to report fair and accurate usage numbers in line with the ethos of Fair Source.

Am I responsible for knowing who within my organization is already using Fair Source software?

Yes. If you are working for a company, we recommend checking with your engineering manager to make sure you don’t accidentally go over your organization’s Use Limitation. If you’re unsure about anything, contact the licensor.

Additional Questions

Can I use Fair Source-licensed products to develop software that will be licensed under different licenses?

Yes, as long as you don’t use any of the Fair Source-licensed code in the software you’re developing.

Who created the license?

Fair Source was created by Sourcegraph and drafted by Heather Meeker.



WIRED (Klint Finley):

…the Fair Source model is one way developers are trying to strike a balance between getting paid and preserving the core values of open source.

First Read: The Fair Source License (Kyle E. Mitchell):

Open source software creates opportunity. But open source also hurts people. Value contributed and value received in return are incredibly out of sync, and have been. We love the people getting hurt too much, and there are too many of them, to get used to the way things are. …

The Fair Source License is a new tool in our lock picking toolkit. It’s not magic, I don’t think it’s universal, and it’s almost certainly not sufficient by itself. But it’s wicked creative, broadly informed, and well implemented.

Open Source, Closed Source, Fair Source (video of talk by Quinn Slack, Sourcegraph CEO, on why Sourcegraph created the Fair Source License)


We are very supportive of the Fair Source license and business model and believe that it will have broad acceptance into the market.

Fair Source License on TLDRLegal