GranCloud is new application for the generation of real-time granular synthesis in the SuperCollider programming environment. Although the software was initially programmed for use in the interactive composition Creo, it was implemented as an independent program for use in any computer music project. GranCloud consists of a set of SuperCollider classes representing granular clouds and parameter objects defining control data for the synthesis. The software is very flexible, allowing users to create their own grain synthesis definitions and control parameters. Cloud objects encapsulate all of the control data and methods necessary to render virtually any type of granular synthesis. Parameter objects provide several simple methods for mapping grain parameters to complex changing data sets or to external data sources. GranCloud simplifies the complex task of generating granular synthesis, allowing composers to focus less on technological issues and more on musical considerations during the compositional process.