The document discusses the working architecture of NodeJs applications. It begins by introducing the speaker Viktor Turskyi and his experience. It then discusses why architecture is important and shares their battle-tested approach. The presentation addresses whether to use monolith or microservices architectures, and recommends starting with a monolith in most cases. It also discusses domain models, services, and controllers. The presentation provides an example of a service class and user registration process to demonstrate the architecture in practice.