Kakao Analyzes Open Source License Trends and Releases Guide for New Licenses like SSPL and Elastic License

Kakao's Open Source Technology Team released a guide analyzing the evolution of licensing from traditional licenses like MIT and GPL to recently introduced ones such as SSPL, Elastic License, and BUSL. The report particularly focuses on licensing issues faced by infrastructure developers when providing cloud services (SaaS), analyzing obligations and risks for each license through case studies.

Key License Change Cases and Characteristics

• Grafana (Apache v2.0 → AGPL v3.0): Source code disclosure obligations apply even when services are provided over a network. When offering services externally, source disclosure obligations must be complied with.
• MongoDB (AGPL v3.0 → SSPL v1.0): Introduced to prevent cloud service providers from 'Strip-Mining' (generating revenue without contributing to open source). When providing services, not only the program but also the entire service source code, including management, monitoring, and backup, must be disclosed.
• Elasticsearch (Apache v2.0 → SSPL/Elastic License dual): The Elastic License prohibits providing hosting services and changing license key protection features. From version 7.11, the applicable license varies depending on the pricing plan.
• Sentry (BSD 3-Clause → BUSL v1.1): Prohibits commercial service usage, but automatically transitions to licenses such as Apache v2.0 after a certain period (e.g., 4 years) following deployment.

The Shift from Open Source to Shared Source Software

The open source ecosystem is entering the era of Shared Source Software, following Free Software and Open Source Software. Shared Source Software includes clauses restricting commercial services to protect intellectual property rights and is therefore not recognized as an OSI-compliant open source license. In response to these changes, Kakao has officially launched its internal license verification tool OLIVE to support developers in license compliance and risk management.