You have been building your applications with stateless microservices. You might even be a rockstar using Kafka for inter service communication. Everything works wonderfully but you feel you could do something more. You want your microservices to have a state. Developing stateful microservices can be hard. I will share my experience with building stateful applications with Kafka and Spring Cloud Stream libraries. Kafka Streams State Stores and Interactive Queries are the main building blocks. They are used by stream processing applications to store and query data. They can scale and be fault tolerant together with your application instances in your container platform. But there are some limitations and we need to know how to monitor their performance. This session is targeted for developers who are interested in learning event streaming practices. Demo application code will be available to participants.