PurposeWhile service scholars see modularisation as balancing the efficiency of standardisation with the value added through customisation the relationships between these concepts are under-theorised. In addition, although information and communication technologies can facilitate all three service strategies, the degree to which they codify service knowledge is not explicitly considered in the extant literature. The purpose of this paper is to develop and validate a model that examines service strategy trajectories by specifically considering the ICTs used and the degree of knowledge codification employed.Design/methodology/approachThis study draws on three qualitative case studies of service departments of firms involved in cardiovascular applications, orthopaedic, spinal and neuroscience product development and information technology support. Data collection involved semi-structured interviews, document analysis and non-participant observation.FindingsFindings show that ICTs were increasingly used to codify both standardised and customised services, though in different ways. For standardised services ICTs codified the service process, making them even more rigid. Due to the dynamic nature of customised services, drawing on experts' tacit knowledge, ICTs codified the possessors of knowledge rather than the service process they undertook. This study also identified a duality between the tacit development of customised services and modular service codification.Research limitations/implicationsThe model is validated using case studies from three companies in the medical and information technology sectors limiting its generalisability.Practical implicationsThe importance of considering the degree of tacitness or explicitness of service knowledge is important for service codification. The paper provides managers with empirical examples of how ICTs are used to support all three strategies, allows them to identify their current position and indicates possible future trajectories.Originality/valueThe papers main contribution is the development of a model that integrates the literature on service strategies with knowledge management strategies to classify service standardisation, customisation and modularisation in terms of both service orientation and degree of ICT codification.