The behaviour of users on the internet is controlled to a large extent by what providers of online platforms enable them to do through a specific design of their service or by what they implicitly prohibit. It is also possible for providers to encourage certain behaviour patterns in users through the design of their user interface and to thereby gently steer the user's behaviour, using so-called nudging. The totality of these controlling factors is called ‘code’ in the debate on governance. A term, that was significantly influenced by legal scholar Lawrence Lessig with his equation ‘Code is Law’ in 1999. Moreover, the behavioural impact on society is potentially increasing due to the possibility of controlling behaviour through code and the growing relevance of internet providers. The PHD-project aims at contributing to the debate on the factor ‘code’ within the legal discourse. Furthermore, it wants to depict the normative content of code and set it into relation with the law. So far, the law has been mostly unfamiliar with explicit points of reference to react to these steering effects. On this basis, it will be examined whether or not and to what extent code can be used as a controlling factor in the sense of a rule-rule-regulation.