This paper presents a design space for interaction with word-scale visualizations. Most sparklines and word-scale visualizations are static and do not support any interaction. However, when word- scale visualizations are used in digital environments, interaction can enhance their use by allowing various data manipulation and man- agement operations. Our design space covers where, when, and how interaction can be triggered for word-scale visualizations em- bedded in a text document. It also includes how and when to transi- tion from a view where the text with word-scale visualizations is the focus (document-centric view) to a view in which the visualizations becomes the reading focus (visualization-centric view).