For a microservices architecture to be succesful it is crucial to have the right boundaries and APIs between the microservices. But where are the right boundaries? And what is the right API? We would like to present a tool that helps us answer these questions. Domain Storytelling is a collaborative modeling method. It brings together domain experts and development teams. We let our users tell us stories about their work. While listening, we record the stories using a pictographic language. The experts can immediately see if we understand their story. After very few stories, we understand the language of our users and find different areas of the domain. Each of these areas (called a subdomain) is a good candicate to become a microservice in our architecture. In this talk we show how to find subdomains and which heuristics can help us.