jsii

jsii is an open-source framework that enables developers to author JavaScript classes once and expose them as native libraries in multiple languages like Python, Java, and C#. It is designed for library authors, particularly those building multi-language SDKs, and is the core technology behind the AWS Cloud Development Kit (CDK). Its key innovation is eliminating the need to maintain separate codebases for each language, dramatically reducing duplication and ensuring consistent behavior across ecosystems.