For a microservices architecture to be successful it is crucial to have the right boundaries between microservices. But where are the right boundaries? We would like to present a tool that helps us answer this question. 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 candidate to become a microservice in our architecture. In this talk, we show how to find subdomains and which heuristics can help us.