The code is written and layouts are drawn so that the company understands and fulfills the needs of its customers faster and more accurately than competitors. To achieve this result, one must understand which tools work and which are of little use in a world of constant change. In my book, I tell you how you can build the internal quality of IT systems and development processes in such a way as to have time to adapt to any changes in the internal and external environment, as well as changing customer needs during the project. One of the key concepts of this study is the concept of “antifragility”. My own entrepreneurial experience and the experience of my partners, clients and friends convinced me that when creating IT products, great attention should be paid to their "antifragility" - the strength, robotic ability of the solutions offered to the client in a changing world.