The bounce API, part of the SAAS product Postmark, has undergone improvements to increase its performance. Initially, a 20% reduction in response times was achieved through optimizing query structure from using `bool` queries to filters. Further research led to another optimization by switching to a `filtered` query structure, which resulted in an average response time of around 140ms. These enhancements demonstrate the importance of continuous improvement and monitoring of existing features to maintain performance and competitiveness.