This Pathways to Enable Open-Source Ecosystems (POSE) project creates new opportunities for innovation in web-based scientific computing, enhances technological competitiveness, and improves data privacy and security for users nationwide. JavaScript, the dominant programming language of the web, currently lacks robust scientific computing capabilities compared to languages such as Python and R. By catalyzing an ecosystem centered on stdlib, a powerful open-source software library for JavaScript and WebAssembly, this project addresses this critical gap. The innovation will empower users and developers to perform sophisticated numerical computations directly within web browsers and edge devices, significantly improving data privacy and performance, and reducing costs associated with cloud computing infrastructure. The development of this technology provides the United States with a durable competitive advantage by establishing leadership in web-based scientific computation, potentially transforming sectors such as education, healthcare, environmental science, and business analytics. By enabling widespread and easy-to-use scientific computation capabilities directly in the browser, this project will benefit educational institutions, businesses, researchers, and government agencies, fostering broader scientific literacy, promoting innovation, and supporting the national interest by advancing the nation's scientific, technological, and economic prosperity. This Pathways to Ena