During a long time, the main development approach was OOP. In this case, the construction of the object model of the subject area in the form of structures of references and documents and business logic in each object is a suitable design method for the analyst, and the developer easily transfer it to the code and the developer can change the model during realization if choose different way. Therefore, the model reflects the code, and complexity of model changes due to new requirements allow to evaluate the cost of development. However, other paradigms for the implementation of high-load applications, such as microservice architecture or the actor model, are becoming quite popular. In this case, analysts need different methods to describe the requirements and domain model, that they are adequate to the programming paradigms. I talk about some of them in my speech.