Everyone is talking about the modern data stack (MDS) nowadays. I am a data system person. I started building core database systems in the big data era, and have witnessed the birth and prosperity of cloud computing over the last decade. But the first time I came across the term “modern data stack,” I felt confused - is it just yet another buzzword that the cloud service vendors created to attract people’s eyeballs? There are so many articles online, but most of them are quite markety and salesy. After running a startup building core systems in the modern data stack domain for a while, I would like to share my thoughts. In this article, I will explain “modern data stack” to you in simple terms, and discuss why modern data stack can really matter in companies.