---
title: Licensing
summary: Which surfaces are MIT, which are BSL 1.1, and what that means for you.
canonical: https://docs.caveman.so/docs/licensing
license: MIT
updated: 2026-08-26T03:57:26+02:00
basis: inferred
---
# Licensing
> Which surfaces are MIT, which are BSL 1.1, and what that means for you.
Caveman uses three licences, one per kind of surface. Which one applies depends on what a piece of code
is, not on how much you use it. Nothing here has a usage threshold that changes your terms.
[Diagram: the licence split across MIT, BSL 1.1 and Commercial surfaces.]
## MIT: adoption and interop
Anything a developer installs to work with Caveman is MIT, and stays MIT inside your commercial product.
The skill, the CLI, the TypeScript and Python SDKs, the Agent SDK and its initialiser, cavekit, the eval
graders, the extension shell, the wire contracts, the provider catalog, and the JavaScript and Python
clients for cavemem.
## BSL 1.1: the engine-linked runtime
The compression engine and everything that links it: the cavemem core, the caveman-shrink core, the MCP
server core, caveman-browse, and the shared platform libraries.
BSL 1.1 is source available, not open source. The distinction is one paragraph long.
### What you may do
Read the source, modify it, run it. Internal evaluation, local development, CI, integration work, and
self-hosted use for your own first-party traffic, production included.
### What needs a commercial licence
Offering Caveman or its functionality to third parties as a hosted, managed or embedded service. That is
the OEM and platform boundary, and it is the only restriction.
### When it becomes Apache 2.0
Each BSL version converts on the earlier of 21 June 2030, or the fourth anniversary of that version's
first public distribution under BSL. The conversion is per release, so an old version converts before a
new one.
## Commercial: Caveman Cloud
Multi-tenancy, verified accounting, governance, billing and the hosted dashboards. These run on our
machines under an account and are not distributed.
## Mixed directories
Two packages ship an MIT launcher around a BSL binary: the MCP server and caveman-shrink. In those
directories the launcher terms are in `LICENSE.launcher`, and the Go source plus downloaded-binary terms
are in `LICENSE` and `BINARY_LICENSE.md`.
## The default for new code
One sentence, quoted because the wording is the rule:
> A new module that imports, links, embeds, or ships as part of Engine-linked runtime is BSL 1.1 unless a
> later ADR explicitly classifies it as MIT adoption surface.
## Contributing
In MIT areas, inbound equals outbound. Your contribution is MIT.
In BSL areas, contributions need a DCO sign-off and a relicense grant to Julius Brussee. That grant is
what makes the eventual Apache 2.0 conversion possible, since a licence cannot be changed on code the
project does not have the rights to change.
## Third-party code
The pixel renderer is a Go port of pxpipe, which is MIT, and uses glyph atlases from Spleen 5x8
(BSD 2-Clause) and GNU Unifont (OFL 1.1, or GPLv2 with the font embedding exception). caveman-browse
vendors chromedp, which is MIT. Notices ship next to the code in each case.
## Trademarks
"Caveman" and the Caveman logos are trademarks of Julius Brussee. A code licence grants no trademark
rights. Nominative use is fine when it is true: "Powered by Caveman" and "Optimized by Caveman" are both
allowed if that is what your product does.
The authoritative text is `LICENSING.md` and `TRADEMARKS.md` in the repository, alongside the licence
files themselves. Where this page and those files disagree, those files win.