Despite the proliferation of over 45000 smartphone mobile health applications (MHAs), as far as we know, there is no MHA for those living with rare diseases such as Bladder Exstrophy-Epispadias-Cloacal Exstrophy complex (BEEC). We hypothesized that an MHA could provide similar "on-demand" information and connectivity within health communities for patients with BEEC as they do for more common diseases. Thus, our primary goal was to create an MHA for patients and families affected by BEEC to provide them with important information about the condition and a format for them to connect with other affected patients and families. A secondary goal was to develop an adaptable MHA template for other rare diseases in the future. We began our app development by examining existing common-disease MHAs for thematic structure. We conducted an extensive literature search of PubMed and Google scholar for MHA development and existing MHAs related to BEEC, utilizing these search terms: mobile health applications, rare diseases, bladder exstrophy, and online health communities. Our app development team began with our clinical multidisciplinary team of pediatric urologists; a child psychiatrist; a patient/family mental health therapist; and a certified nurse practitioner. We hired a website engineer and a production team. All clinical members have extensive experience caring for children and families affected by BEEC. Additionally, clinical team members compiled lists of themes deemed relevant from these reviews and themes gleaned from their clinical experience that appear with some frequency or urgency and from the myriad of themes discussed within the literature for MHAs. We found no existing rare disease MHAs in the literature or our search of app stores online. However, we derived basic app categories from existing MHA formats and the thematic content of all sources reviewed. These categories aligned with the groupings of our lists of clinical themes. Thus, we could subsume diverse themes within a broad categorical format: for example, child development (as "Psychological Development" in the app) or various clinical care options (as "Treatment"). This app structure became nine sections, as shown in. This format allows diverse information to be retrieved efficiently from broader categories. This app is being offered to affected families, healthcare providers, and individuals unrelated to where care is offered. "We the BE" is the first MHA developed for a rare disease, BEEC. It has been published in a downloadable format for the general public at no cost. Further research is required to determine its efficacy for the BEEC community members; preliminary, unsolicited feedback from multiple users has been positive.