Sustainable License: Frequently Asked Questions

Update: For the latest copy of these FAQs, please see this GitHub repo.

Sustainable License v1.0

1. Can you summarize what is allowed with the Sustainable License 1.0?

Sustainable License allows the right to use, modify, create derivative works, and commercialize, with these limitations:

  • You may not circumvent the monetization module.
  • You may not remove or obscure any licensing, copyright, or other notices.

2. What is a monetization module? What does it do?

Sustainable License follows an open pricing model. The pricing and the charging mechanism for the software are baked into the software itself, in a module we call the monetization module.

3. Is Sustainable License Open Source?

No. Sustainable License imposes limitations around modification of the monetization module, which is against OSI guidelines.

4. Is Sustainable License Free Software?

No. Sustainable License imposes limitations around modification of the monetization module, which is against FSF guidelines.

5. Is Sustainable License Proprietary?

Not quite. Most proprietary softwares do not come with the source code, or encourage sharing and commercialization. Sustainable License allows the software to be modified, redistributed and commercialized.

6. Is Sustainable License EULA?

No. EULAs do not allow users to change or distribute code.

7. Is Sustainable License Freeware?

No. Freeware is software that is distributed at no monetary cost to the end user. The source code is typically not made available. Sustainable License is the opposite of freeware, where the source code is freely available to modify, but comes at a monetary cost.

8. Is Sustainable License Shareware?

No. Shareware is a type of proprietary software which is initially shared by the owner for trial use at little or no cost with usually limited functionality or incomplete documentation but which can be upgraded upon payment. Code under Sustainable License is expected to be provided with full functionality with no upgrades beyond the enforced monetization.

9. What is Sustainable License?

Sustainable License is a very liberal commercial license. The only main limitation Sustainable License adds is to ensure a source of income for the developing entity. Beyond that, it provides all the liberties expected from a free and open source software, which includes modifications, redistributions and commercialization, without discrimination.

We think Open Source has taken hits recently with many open source companies moving away from it to use non-open-source licenses (SSPL, Elastic License, various community licenses) to eliminate competing SaaS offerings. Sustainable License provides an alternative solution which doesn’t forbid commercialization of the software by anyone. We think software commercialization is NOT a zero-sum game, the more participants in the economy, the better for end-users and everyone can win.

There have been many instances where the software becomes popular, but the developers behind the software are left high and dry, unable to balance their financial needs against the time and effort it takes to maintain the software, ultimately giving up on the software and moving on.

Sustainable License is a practical solution to that, while staying true to the many liberties promised by FOSS. We believe users are willing to pay for the software that benefits them. And by charging for the software, Sustainable License creates the right alignment between the developers and the users, hence ensuring the longevity of the software which is the best outcome for everyone.

10. How does Sustainable License compare against Elastic License?

Sustainable License 1.0 is modeled after Elastic License 2.0 but differs in the limitations it imposes. Elastic License 2.0 has this limitation, that Sustainable License 1.0 does NOT have:

~ELv2: You may not provide the software to third parties as a hosted or managed service, where the service provides users with access to any substantial set of the features or functionality of the software.~

As mentioned above, we encourage managed service providers to make this software as widely available as possible. Elastic License 2.0 has this limitation, which Sustainable License 1.0 has modified:

~ELv2: You may not move, change, disable, or circumvent the license key functionality in the software, and you may not remove or obscure any functionality in the software that is protected by the license key.~

SLv1: The software contains a module that allows the licensor to monetize your use of the software. You may not move, change, disable, or circumvent this functionality in the software.

11. Can I provide a managed service using a project under Sustainable License?

Absolutely. As opposed to other such licenses (like Elastic License or SSPL), Sustainable License allows building commercial products, including building managed services. In fact, we encourage others to do so, to make this software as broadly available as possible for end-users.

12. If I fork the codebase, do I need to make my derivative work publicly available?

No. If you fork the codebase and make modifications, those changes can stay private. You have no obligation to make that public. You can even commercialize this fork by charging for the software (at a higher price than what you’re paying), linking it to your proprietary code, or creating proprietary services around the fork.

However, the fork must continue to abide by the limitations of the Sustainable License, which includes keeping the monetization module, licensing, copyright, and other notices.

13. If I copy only certain parts of the code into another program, do I still need to pay?

Yes. If you copy any part of the codebase under the Sustainable License, your program should pay and do the equivalent of what the monetization module would have done.

If you use any of this software, you must keep and not circumvent the monetization module. You can’t use only other portions of the software.

14. Why build this license? Why charge for this software?

We have built a lot of open-source software in the past, with none of them providing any source of income for the developers. Currently, there are three ways to fund the development of open source.

  1. Use your personal savings to fund the development. Or, have your company fund the development of the project.
  2. Build open-source part-time while working for another company, if they allow that.
  3. Take money from VCs. This generally results in building proprietary features and a cloud-managed service to monetize the software.

Option 1: If possible, this is the best way to go. But, might not be available as an option for most developers.

Option 2: For work-life balance, this option is highly unwieldy.

Option 3: Once you take VC money, it becomes your fiduciary duty to optimize stockholder interests. To generate revenue, developers often mix open-source (free) features with proprietary (paid) features (also known as the open core model), which causes a rift for the developing team between how much do you give away for free” and what do you charge for. Moreover, the proprietary features typically come with opaque pricing models for on-premises deployments.

The second and the most widely used revenue stream is to provide a cloud-hosted solution. To maximize the revenue there and eliminate competing SaaS offerings, the license is usually changed to a non-open-source license which explicitly disallows others from building similar services.

We think none of these options are particularly attractive in a world where users are increasingly willing to pay for the software, as long as the pricing model is open and fair to all.

With Sustainable License, we aim to hit the nail on its head. Make the software charge for its usage with an open pricing model baked into the code itself, available and visible to everyone. And provide as much freedom as possible for others to use, modify or build commercial services around the software.

TL;DR: A software under Sustainable License provides a direct income stream to the developer so they can focus on the software while eliminating the rift between free v/s paid feature set, opaque pricing models, or disallowing others from building commercial services.

15. Can I apply Sustainable License to my project?

Yes. We think more developers should be using Sustainable License to make a living out of their hard work.

The best application for Sustainable License is standalone servers. It can also be applied to heavy-weight libraries, where the developer believes a payment for usage is justified.


July 18, 2022