licensecompatibility

License compatibility refers to whether code released under one license can be legally combined with code released under another license in a single distributed work without violating the terms of either license. It addresses how the licenses’ requirements interact when components are integrated or when derivative works are created.

Key factors include the license type and the nature of the integration. Permissive licenses (such as MIT, BSD, and Apache 2.0) generally impose fewer restrictions on redistribution and are often compatible with many other licenses. Copyleft licenses (such as GPL family and some weak copyleft licenses) require that derivative works or certain distributions be licensed under the same or compatible terms, which can create incompatibilities if combined with licenses that impose conflicting conditions.

Common patterns and examples. Code under permissive licenses can usually be incorporated into projects licensed under copyleft terms, with the overall distribution then governed by the copyleft license. For instance, MIT- or BSD-licensed code can be included in a GPL-covered project, with the combined work distributed under the GPL. Apache-2.0 licensed code is generally compatible with GPLv3 projects, but Apache-2.0 is not compatible with GPLv2-only code. Licensing dynamics can be more complex for licenses with file-level copyleft or patent provisions, such as MPL or certain commercial licenses, where only parts of a project may be subject to specific terms.

Practical guidance. When assessing compatibility, consult the exact license texts, consider whether you are distributing a derivative work or a mere aggregation, and note any version-specific rules. SPDX identifiers and compliance tools can help, and when in doubt, seek legal counsel.