BackgroundAdolescence represents a vulnerable period to experience personal crises or mental health problems. However, many concerns stay unnoticed due to the hesitance of young people to seek help and the unavailability and inaccessibility of appropriate help services. Contemporary interventions have been developed incorporating with target group specific needs and preferred modes of communication. krisenchat (German for “crisis chat”) is a German low-threshold chat-based psychosocial crisis counselling service that is available around-the-clock. Despite the growing number of online support services, there is a dearth of research regarding the acceptability, usability, and feasibility. MethodsThe present cross-sectional study analyzed retrospective anonymous data on sociodemographic variables, utilization behavior, and user satisfaction of all krisenchat users between May 2020 and July 2021. Predictors of user satisfaction were identified using exploratory multiple regression analysis. Subgroup analyses were conducted using chi-square-tests to identify differences in user satisfaction. ResultsData of N = 6962 users was included in the analysis. More than 50% of those reported not having contacted the professional health care system before. The mean user of krisenchat was 17 years old (M = 16.6, SD = 3.5), female (female: 83.4%, male: 14.7%, diverse: 1.8%), and first approached the service at 4 PM (M = 4:03 PM, SD = 5:44 h). More than 60% of the users contacted the service between 4 PM and 12 AM, 10% even between 12 AM and 8 AM. The most frequent chat topics were concerns regarding psychiatric symptoms (60.1%), psychosocial (34.0%) or emotional distress (30.2%). The majority of the users (64.7%) reported high levels of satisfaction and 88.3% a high likelihood (60% or more) of recommending krisenchat to others. Also, the results indicate that the number of messages and their respective length differed between users and counsellors, with users writing several, but shorter messages and counsellors replying with fewer, but longer messages. ConclusionThe results of the present study imply a high acceptability and feasibility of krisenchat. Overall, there is a high need for a 24/7 messenger-based chat counselling service in crises for children and young adults. Currently, there is no other online service for youth that is available after 7 PM or at weekends, which indicates the great importance of krisenchat and its function to bridge a current gap in the mental health care system. A need for further research emerges e.g., for subgroup differences regarding utilization patterns and also for further insights regarding help-seeking behavior via social media in youth. Study registrationDRKS00026671.