BSL

A license model (popularized by MariaDB and adopted by HashiCorp, Sentry, and others) where source code is publicly available but commercial use is restricted for a set period (typically 3-4 years), after which the code converts to an open-source license. BSL attempts to balance open development with commercial protection. It is explicitly not open source by OSI's definition, which matters for procurement policies that require OSI-approved licenses.