Women remain significantly underrepresented in technology fields, with only 28% of engineering graduates and 22% of AI professionals being women globally. Women in tech communities serve as crucial support networks but face communication challenges that limit their effectiveness, particularly in leveraging personal narratives on digital platforms. This research presents FemTellers, an application prototype developed through participatory design to optimize storytelling strategies for these communities. Based on doctoral research involving 247 Brazilian and Portuguese technology organizations, we identified that these communities’ activism occurs across fragmented commercial platforms, limiting their ability to effectively collect and utilize testimonial narratives. Despite dominant computer literacy among members, communication and storytelling remain challenging. Our empirical work showed that are not present in standard digital platform mechanisms for engaging through storytelling, with communication scattered across multiple channels. FemTellers addresses these challenges as a browser extension working across social network interfaces. It enables community members to flag, discuss, and vote on relevant testimonials found across digital channels, helping identify powerful stories that might otherwise be overlooked. The prototype was developed using Figma and tested with 15 in-person participants at University of Aveiro and six online leaders from Brazilian Women in AI community. Development followed feminist HCI frameworks, specially Bardzell & Bardzell's. Usability results showed participants found the system intuitive and appreciated its integration with existing platforms without requiring migration. The prototype represents a practical application of Feminist HCI principles, creating paths for activism customized to community values while making invisible narratives more prominent for education and empowerment strategies.