This study presents a temporal analysis of user engagement, technology trends, and emotional dynamics on Stack Overflow across the pre-COVID, during-COVID, and post-COVID periods. Understanding these changes is crucial to identifying long-term shifts and enhancing digital engagement strategies in online developer communities. This is especially important during global disruptions like COVID-19, which reshape work patterns, collaboration, and community interactions. In this study, users were categorized by reputation and badges based on Stack Overflow’s reward system. For example, regular users were regarded as newer contributors, intermediate users are moderately active participants, and expert users are those who are highly trusted and recognized for their significant contributions and expertise. Our analysis revealed that engagement declined post-COVID, with regular users experiencing the steepest drop. Intermediate users showed signs of disengagement, strengthening the phenomenon of ‘leaky pipeline’, while expert users recovered the fastest in terms of engagement post-COVID. Technology trends shifted toward full-stack development and AI, and emotional analysis indicated high confusion and frustration during COVID, followed by increased admiration and approval after the pandemic, reflecting improved knowledge exchange. These findings provide actionable insights for fostering sustained participation and inclusivity in technical communities.