"Interviews for UI developers will be full of technical questions about HTML, CSS, and other related software tools. Employers will be looking for candidates who can quickly and correctly answer these questions and who are able to show creative and appealing user interfaces that they have created in the past. A bachelor's degree or equivalent work experience is necessary for this position."
Basic reversing a JSON data. Postfix calculations, and high level understanding of your experience with visualizations (D3).