🛡️ RISK BADGE: 🔴 RESTRICTIVE (Source Available)
Executive Summary: What is it?
The Functional Source License (FSL) is a modern "Source Available" license pioneered by Sentry. It grants developers the right to copy, modify, and redistribute the code for any purpose except providing a competing commercial service. It is NOT an Open Source license (OSI definition) during its initial term.
CFO / Business Impact: What does it cost/risk?
The "Anti-AWS" Protection. For 99% of enterprises, FSL is functionally free and safe. You can use it for internal tools and production backends without cost. The SaaS Restriction: You cannot host the software as a managed service to compete with the original creator. The 2-Year Freedom Guarantee: Every version of FSL-licensed code automatically converts to a permissive license (MIT or Apache 2.0) exactly two years after its release, ensuring no long-term vendor lock-in.
Technical Reality: How does it work?
It acts as a "timed" license.
- Initial Phase: Source is available and editable, but commercial SaaS usage is restricted.
- Change Date: On a specific date (2 years post-release), the license for that specific version legally "flips" to a standard Open Source license. This provides a compromise for sustainable business models: protecting revenue today while guaranteeing digital sovereignty tomorrow.