Evaluating and Improving Accessibility of Web Applications: Zulip Chat Case Study

Web applications are built to be accessible to everyone. Unfortunately, many web applications are inaccessible to people with special needs or disabilities. In this work, we show a methodology used to make web applications more accessible to a diverse group of people. The process includes two phases: evaluation and improvement. In the first phase, the Web Accessibility Barrier (WAB) score metric together with the Accessibility Failure Rate (AFR) metric are used to evaluate web applications. In the second phase changes suggested by accessibility checker tool are implemented in the software to enhance the metrics values and reach the target level of accessibility. The open-source chat application, Zulip, is used as a case study to show the effectiveness of this approach.