A practical (developer-focused, rather than legal-focused) history and description of the Business Source License (BSL). Introduced by MariaDB in 2016, the BSL: The source code is publicly available. Non-production use is always free. “Usage limitation” allows some provisions for limited production use as specified by the licensor. Most companies use this as a way to enable any production to be used except for ones deemed competitive (e.g., offering a competing managed service). Others, like MariaDB, put a limit on how many servers you can run in production without an additional license.