Hypothes.is is a web-based annotation platform that enables users to annotate online documents and share their annotations with others. Supported by the Sloan Foundation from conception through prototyping, the platform now has 10,000 regular users and is seeing increasing use among lawyers, journalists, and academic researchers. Interest from the academic publishing community has been particularly noteworthy, as several publishers have developed their own, expensive, internal annotation systems as part of their publication review and editing process. This grant supports efforts by Hypothes.is to move the platform away from philanthropic support and toward independent financial sustainability. Grant funds support the hiring of a head of business development, software modifications that will allow the platform to function on a software-as-a-service model; and the creation of administrative interfaces for client publishers.