This chapter describes how researchers and developers may improve the design of technical innovations for crisis communicators by testing how user-friendly the innovation is for its intended end users. In the RESCUE project, a tool for social media information gathering was developed. During this process, tool usability was thoroughly tested. Good usability allows the user to complete tasks and achieve goals with effectiveness, efficiency and satisfaction. The purpose of the r Klas Backholm, Joachim Ho¨gva¨g, Jørn Knutsen, Jenny Lindholm and Even Westvang. Published by Emerald Publishing Limited. This article is published under the Creative Commons Attribution (CC BY 4.0) licence. Anyone may reproduce, distribute, translate and create derivative works of this article (for both commercial and non-commercial purposes), subject to full attribution to the original publication and authors. The full terms of this licence may be seen at http:// creativecommons.org/licences/by/4.0/legalcode 185 usability testing was to strive for a tool that is easy to use during demanding circumstances and contributes to a high level of situation awareness (SA) among users. SA is about being aware of what is happening around you À during, for example, emergency assignments À and what this means for your ongoing work tasks. The main focus of this chapter is to describe how usability testing was applied throughout the tool development process, from the pre-production planning phase to the final phase. As a part of this, the tool features are described.