Indonesia has great potential for asset waqf and cash waqf. Technological advancements show significant growth through fintech platforms for donations, zakat, and waqf. However, the magnitude of the potential of waqf and the advancement of financial technology is not in line with its realisation; this is a fundamental problem in Indonesia. The study aims to analyse the support of online waqf, an approach to waqf behaviour in Indonesia, by examining the influence of waqf literacy, trust, and attitude on behavioural intentions and behaviour of users who pay online cash waqf with age as a moderating variable. The study used a quantitative method with a survey approach to waqif in Indonesia, totalling 242 respondents through purposive sampling domiciled on the island of Java. Data analysis uses a structural equations model with the partial least squares (SEM-PLS). The study found that waqf literacy, beliefs, and attitudes have a significant relationship and a positive influence on behavioural intentions and user behaviour. Age has a significant impact on moderating the relationship between literacy and behavioural intentions. Behavioural intentions are significantly related to online waqf user behaviour. The implications of the research are increasing the support of literacy, trust and attitude to increase the potential for the realisation of online waqf in Indonesia, especially on the island of Java. The waqif behaviour approach strengthens the literature on Muslim social contributions. Further research examines the behavioural aspects of online waqf recipients (nazir) with qualitative and quantitative method approaches.