Following a design-oriented methodology, we aim to support unemployed people facing complex barriers like drug addiction or poverty by designing and evaluating an online intervention that complements traditional face-to-face offline counselling with online peer groups. Our peer-group-based job counselling approach provides peer support in an intimate environment, independent of time and place. We implemented our approach at the German Federal Employment Agency with a messaging application and evaluated it in a randomised field experiment and expert interviews. Results indicate that the approach adds substantial value compared to face-to-face offline counselling, particularly with respect to job search self-efficacy, self-exploration, and environmental exploration – proven success indicators for the employment of unemployed people with complex barriers. It further demonstrates the benefits of online characteristics and how online peer groups and offline interventions can cross-fertilize in this context. Our study contributes to the literature on the societal impact of information and communication technologies and to design science research, and answers stake-holders’ call for modernisation of employment counselling in practice.