This work describes The Lean Development methodology that can be used for managing development without known customer. Moreover, it describes the development of an already finished project - a web application that did not involve this methodology. After that this work finds out which aspects of this development would change, if the Lean Development methods were integrated, and proposes a specific solution for subsequent development, compliant with this methodology. At the end, this work presents the list of activities that the development team must pass when developing without known customer.