Licensing
Open source, with a commercial door
x64base is dual-licensed. It is free and open source under the GNU General Public License v3 (GPL-3.0-only, committed to the repository 2026-08-11) for everyone, and available under a separate commercial license for anyone who wants to use it in a closed or proprietary product.
1. Open source (GPLv3) -- free for everyone
Read it, run it, study it, teach with it, fork it, and preserve it -- at no cost, forever, under the terms of the GPLv3. Students, educators, hobbyists, researchers, and the retro / xBase community never pay. If you distribute a modified version, the GPL asks only that you share your changes under the same license.
2. Commercial license -- for closed or proprietary use
If you want to embed x64base in a closed-source or commercial product, or use it on terms other than the GPL, a commercial license is available from the author. This is the only situation in which anyone pays for the engine itself. Contact us to discuss terms.
3. The value layer -- optional, and gates nothing
The engine is free. What is offered for support are the things built around it: teaching materials and an "inside the engine" curriculum, architecture and lineage documentation, workshops and lectures, and institutional support or consulting. You are never buying access to the code -- only the teaching and understanding around it. Sponsorship is welcome and gates nothing.
Educational and non-commercial use is already free under the GPL. Accredited institutions that need commercial terms may request them at no or nominal cost.
The license covers the software; project names remain the author's.