The software company AFRY licenses out a Product Support System (PSS) called AFRY Pulse, which serves as a backbone for businesses to deliver value to customers, employees, and stakeholders. Currently, AFRY Pulse lacks offline support, putting them at a disadvantage compared to competitors offering similar PSS solutions. Therefore, this study aims to implement offline support for one of AFRY Pulse's modules, called the Round Module, with the help of Service Worker API.  Based on the problem formulation, the study investigated how well the implementation of the Service Worker API matched the “Must have” requirements, specified in the requirement specification and identified complications that arose during implementation, along with their solutions.  The implementation of offline support followed an agile software development approach with three and a half sprint iterations. Each sprint involved specifying requirements, implementation, and evaluation sessions. The data collection methods used includes maintaining a journal, with notes taken during the implementation and the evaluation sessions. The evaluation sessions included manual black-box testing, manual code-review, and semi-structured interviews.  The results from the evaluations produced two themes Implemented correct functionality and Improving visual response. Furthermore, the complications that were found during the implementation were Service Worker going to the redundant state, Service Worker not being able to stop fetch requests and AbortController being redundant within the Service Worker.