People working with vulnerable groups of youth are struggling on a daily basis with the problem of maintaining work-life balance. Youth with physical disabilities, behavioral problems or intellectual disabilities, youth from alternative care, NEET youth and minorities face difficult problems in their everyday lives that can trigger strong feelings of empathy, sadness, helplessness or anger in youth workers. It can be very hard for youth workers to get proper rest after work and don’t think about distressing problems that young people they work with face. Most jobs and many life experiences generate some degree of stress but it seems that this problem is exacerbated among individuals working in emotionally demanding environments. The professional sphere often spills over into worker’s private life, and worker experiences a burnout. In order to achieve work sustainability, workers should find a balance between work and private life. Considering that we are lacking tools to help youth workers to alleviate the stress and emotions arising from such emotionally demanding work, development of a modern tool that is easily applicable and simple to use is of utmost necessity.Youth workers who learn how to take care of their mental health will be able to teach these skills to young people they work with too. When adopted, these skills make our daily lives more meaningful and enjoyable, even when we are faced with difficult situations and circumstances. Acceptance and commitment therapy (ACT) is a form of cognitive-behavioural therapy, an empirically based psychological intervention that uses acceptance and mindfulness strategies with commitment and behavior-change strategies to increase psychological flexibility. Psychological flexibility is the ability to stay in contact with the present moment regardless of unpleasant thoughts, feelings, and bodily sensations, while choosing one's behaviors based on the situation and personal values. Studies show that psychological flexibility is associated with quality of life and mental well-being.Unfortunately, the traditional face-to-face psychotherapy is usually too expensive or inaccessible to youth workers working with vulnerable groups of youth, especially to those living in rural or poor areas. Computerized cognitive-behavioural treatments show promising results in treating anxiety and depression symptoms, as well as in development of healthy ways of dealing with stress. That is why this project will use this modern approach to enable greater number of youth workers to learn and implement basic principles of ACT treatment for their own self-development and in their everyday work with young people.The objective of this project is to introduce psychological flexibility skills into youth work practices with the aim of empowering professional capacities of youth workers that work with vulnerable groups of young people. As a result, they will be able to cope with stress more successfully, protect themselves from burn-out and transfer those skills to the young people they work with. This objective will be achieved by development of an intellectual output: innovative tool for increasing psychological flexibility that will consist of 2 parts: workshop curriculum that will be used in synergy with the mobile application containing short excercise based on the principles of ACT therapy. The app will be available for use in 3 different ways: individually by youth worker, individually by the young person, or in group work.Target group of this project are youth workers from 5 participating countries who will take part in producing the described intellectual output, piloting it and disseminating it to the relevant stakeholders. In the beginning of the project, 10 team members will take part in joint staff training where they will learn the basics of ACT treatment that will enable them to develop the content for the curriculum and the app. The developed materials will be tested and revised in the second joint staff training that will be organized for additional 15 youth workers who will implement national piloting of the materials afterwards. Through these trainings, youth workers will develop their own psychological flexibility and with the help of the developed intellectual output, they will be able to transfer these skills in a systematic and easy way to young people they work with. The developed curriculum and mobile app will be freely available in the project website and widely disseminated to other youth workers who want to develop better ways of dealing with stress and transfer these skills to youth they work with. The expected impact and long-term effect of this project is raising awareness of the stress that youth workers who work with vulnerable groups of youth deal with in their everyday work, of the importance of adopting healthy ways of dealing with stress and taking care of own mental health for lifelong sustainability, especially in such high-demanding emotional work.