Stateless is the most common approach for developing microservices. There are many reasons for this, but in short: very simple, very reliable, and of course, very scalable. But as we all know - there is no silver bullet. Some time ago, we faced certain limitations of this approach. Spoiler, Stateless turned out to be very slow, less reliable, and also more expensive. In my presentation, I will try to cover the following topics: Why we chose the Stateful approach instead of the Stateless and what our architecture looks like. How we build and manage Stateful services: service scale-out, data consistency, synchronization, and partitioning(sharding). Why Stateless services are less reliable and quite slow. What tools can we use for building Stateful services.