Explorables with interactive, multimodal content, openly available on the web, are a promising medium for education. Yet authoring such explorables requires web development expertise, excluding most educators and students from the authoring and remixing process. Some tools are available to reduce this barrier of entry and others are in development, making a method to evaluate these new tools necessary. On the basis of the software quality model ISO 25010, empirical results, and domain modeling, we derive the Explorable Authoring Requirements (EAR) as a requirements catalogue explorable authoring tools should implement. We then outline a future research design to operationalize EAR.