Adolescent and young adult (AYA) cancer patients report a need for support to stay in contact with loved ones after diagnosis. In response to this the Dutch AYA 'Young & Cancer' Care Network co-created the mobile application 'AYA Match'. This study describes the cocreational process, the characteristics of the users and their expectations regarding the app. 121 AYA cancer patients and 37 loved ones completed a questionnaire. 68.6% of the loved ones reported 'staying in contact' and 'finding out about the needs and wishes of 'their AYA' during this time' as the main reasons for downloading the application. 41.1% of the AYA cancer patients expected the app to help them communicate to their loved ones what they do or don't want and need. 60% of the loved ones indicated that they would like to use the application to offer help to 'their AYA' with their daily tasks. Patients and their loved ones have similar expectations when it comes to 'normalizing' contact, increasing empathy and mutual understanding about needs and emotions. The AYA Match app could be an adequate answer to the issues experienced regarding contact, support and mutual understanding.