The article substantiates the relevance of developing digital competence in future computer science teachers through informal education as a strategic direction for professional training in the context of society's digital transformation. The essence of the concept of 'digital competence' is defined as an integrative formation that encompasses technical, cognitive and ethical components. The role of informal education as a tool for flexible and dynamic updating of professional knowledge and digital skills is emphasised, which meets the needs of individualisation, adaptability and independent professional development. The potential for integrating formal and informal education into the process of professional training of teaching staff is outlined, and conceptual foundations for building an effective model of digital education based on a combination of traditional and innovative approaches are proposed. Particular attention is paid to the principles of variability, modularity, fractality, and openness in the education system, which enable the content and structure of training to be adapted to the challenges of the digital age. The author presents approaches to creating open educational ecosystems that involve cooperation among higher education institutions (HEIs), IT companies, professional communities, and non-governmental organisations. The conclusion is made about the need to revise traditional models of professional training for future computer science teachers, and the prospects for further research in the direction of combining formal and informal educational practices are substantiated.