License & attribution
Keystone is free, and built on open-source principles. It also stands on a stack of open-source tools, and it observes their licenses carefully — both in what it ships and in how it's licensed to you.
An open engine
The engine is open in the way that matters to you: it ships in full inside the
core template — yours to read, inspect, and change, with nothing to
reverse-engineer.
The canonical repository that assembles Keystone's templates and image is private, and will stay so for now. Keystone is modular by design, and Knight Owl LLC builds on it directly — including proprietary and patented work. The parts that make your books are in your hands; the workshop behind them is ours.
Keystone's license
The Keystone template and its assets are released under the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License (CC BY-NC-SA 4.0). In short, you are free to share and adapt it, under three terms:
- Attribution — give appropriate credit, link to the license, and indicate any changes you made.
- NonCommercial — you may not use the material for commercial purposes, including offering it as part of any paid service or hosted platform.
- ShareAlike — if you remix or build upon it, distribute your contributions under the same license.
The license adds two specifics worth calling out:
- Use it to make your own books. Use of the template is permitted solely for creating, modifying, and publishing your own documents and books — that's the intended use. The license governs the template and its assets, not the documents you create with it; your manuscript is your own work.
- Don't repackage it as a product. You may not use the template or its derivatives as part of a commercial SaaS product, build service, or template offering without express written permission from Knight Owl LLC.
This page is a summary. The binding terms are the license itself: see the
license summary and the
full legal code,
and the Keystone.md license file included in every template under .licenses/.
Components Keystone builds on
Keystone produces your books with established open-source software —
Pandoc, LaTeX, and a
curated set of fonts among them — and it respects each of their licenses (for
example, Pandoc under the GPL). The relevant notices travel with every template,
in the .licenses/ directory and NOTICE.md. Keep them in place; they're part
of honoring the work Keystone is built on.
Attribution
Keystone is developed and maintained by Knight Owl LLC. If you build on the template itself, the CC BY-NC-SA terms above apply — credit, a link to the license, and a note of any changes.