Hypothes.is is a non-profit organization founded in 2011 and based in San Francisco, California. It offers an open-source platform designed for collaborative evaluation of information, allowing users to engage in sentence-level critique, discussion, and note-taking across a variety of content, including news articles, scientific papers, and legislation. The platform aims to enhance the quality of information available on the Internet by fostering community interaction and promoting interoperability through software development and adherence to annotation standards set by the W3C Web Annotation Working Group. Hypothes.is is funded by various foundations, including the Knight, Mellon, Shuttleworth, Sloan, and Helmsley Foundations, as well as individual contributions. By partnering with developers, publishers, academic institutions, and researchers, Hypothes.is seeks to advance the next generation of read-write web applications, encouraging participation through its tools and community initiatives.