Trans technology – technology created to help address challenges that trans people face – is an important area for innovation that can help improve marginalized people’s lives. We conducted 104 interviews with 115 creators of trans technology to understand how they involved trans people and communities in design processes. We describe projects that used human-centered design processes, as well as design processes that involved trans people in smaller ways, including gathering feedback from users, conducting user testing, or the creators being trans themselves. We show how involving trans people and communities in design is vital for trans technologies to realize their potential for addressing trans needs. Yet we highlight a frequent gap between trans technology design and deployment, and discuss ways to bridge this gap. We argue for the importance of involving community in trans technology design to ensure that trans technology achieves its promise of helping address trans needs and challenges.