Every time Skales comes up on Hacker News or Reddit, someone comments that it is "not really open source." They are correct. Skales is source-available — you can read every line of code, but you cannot use it commercially without a license. This post explains what that means precisely, why we made that choice, and what it costs us and our users.
What Open Source Actually Means
The Open Source Initiative has a precise definition. For software to be OSI-approved open source, it must allow free redistribution, must include source code, must allow derived works, must not discriminate against persons or groups, must not restrict other software, and — critically — must not restrict commercial use. MIT, Apache 2.0, and GPL are all open source by this definition. Anyone can take MIT-licensed code, use it in a commercial product, and never pay the original author a penny.
MIT: Maximum permissiveness. Use it however you want, commercial or non-commercial, just keep the copyright notice. No requirement to share modifications.
GPL (GNU General Public License): Copyleft. You can use it commercially, but any software you distribute that incorporates GPL code must also be GPL. Forces derivative works into the open source ecosystem. Controversial in commercial contexts.
Apache 2.0: Similar to MIT but with an explicit patent grant. Commercial use allowed. Common in enterprise open source.
What Source Available (BSL-1.1) Means
The Business Source License 1.1 was created by MariaDB as a sustainable alternative to traditional open source for commercial software. Key terms: the source code is fully visible (hence "source available"). Non-commercial and internal use is free. Commercial deployment — using the software in a product or service you sell — requires a paid license. After a specified period (in Skales' case, 4 years from any given release), the code converts to Apache 2.0, becoming fully open source at that point.
Why We Chose BSL Over MIT
The honest answer is sustainability. Building and maintaining Skales requires significant ongoing work — new features, security updates, provider integrations, platform compatibility. MIT licensing would mean any company could take the entire codebase, build a paid product on top of it, and contribute nothing back. This is not hypothetical — it happened repeatedly to projects like Elasticsearch and MongoDB, which ultimately migrated to BSL for the same reason.
BSL lets us keep the code fully transparent (you can audit every security decision, every data flow, every API call) while maintaining a commercial model that funds continued development. The 99% of users who use Skales personally pay nothing and have no restrictions. The 1% of enterprises that build commercial products on top of Skales' work are asked to compensate for that value.
What This Honestly Costs
Skales is not eligible for some open source grants, foundations, and programs that require OSI-approved licenses. Some developers will not contribute to BSL projects on principle — a position I respect, even if I disagree with its application here. There is legal uncertainty for edge cases between personal use and commercial use. And there is the optics problem, which is why this post exists: "not open source" can sound like a red flag even when the source is fully visible.
What You Get
For personal users: completely free, forever, with access to the full source code on GitHub. For businesses: clear commercial terms, a project that will still be here in five years because it has a funding model, and the knowledge that the people maintaining it have aligned incentives with the product's quality. See the FAQ for more on the license or contact us for commercial licensing questions.