📜 LICENSE CLASS: 📖 SOURCE-AVAILABLE
Executive Summary: What is it?
The Functional Source License (FSL) is a "Source Available" license. It grants the right to use, copy, modify and redistribute the code for any purpose except a Competing Use: making the software available to others in a commercial product or service that substitutes for it, substitutes for another product or service the licensor offers using it that already exists when that version is released, or offers the same or substantially similar functionality. It is NOT an Open Source license (OSI definition) until each version converts.
CFO / Business Impact: What does it cost/risk?
- Internal Use: The license permits it by name, with non-commercial education, non-commercial research and professional services to a licensee, at no license fee. You can run it for internal tools and production backends.
- The Competing-Use Line: The limit is functional, not a revenue threshold: a commercial product or service that offers the software's functionality to others is excluded, whatever its size.
- The Two-Year Conversion: Each version becomes available under its future license, MIT or Apache 2.0 depending on the variant (FSL-1.1-MIT or FSL-1.1-ALv2), on the second anniversary of its release, and that grant is irrevocable. The restriction only ever covers code less than two years old.
Technical Reality: How does it work?
It acts as a "timed" license.
- Initial Phase: Source is available and editable, but a Competing Use is excluded.
- Conversion Date: Two years after a version's release, that version becomes available under MIT or Apache 2.0. This offers a compromise for sustainable business models: the licensor's newest code is protected from competing use, while every version becomes open source two years after its release.