Abstract: A method, system, and architecture for a font service and a software development kit (SDK) to provide developers with the means to design user-interfaces and content using a wide variety of font typefaces. The SDK may download a font from a font service as needed and activate the font to be rendered in the software application's user interface or other textual content within the application. A subscription service may be provided which comprises user account information or other data relating to permissions for one or more client devices to access one or more font files located in a font library. Further, one or more font files may be optimized according to an operating system in which the target application is operating and/or a screen resolution of a client device on which the target application is operating.