The Graphiql tool is very useful for exposing the self-documenting nature of APIs.The single responsibility of this service is authoring data and publishing the events, using database-first Event Sourcing, for a specific bounded context..The code within the service follows a very repeatable coding convention of types, resolvers, models, connectors, and triggers..As such, it is very easy to reason about the correctness of the code, even as the number of business domains in the service increases.That’s why it is reasonable to have a larger number of domains in a single authoring BFF services, so long as the domains are cohesive, part of the same bounded context, and authored by a consistent group of users.We hope you found this tutorial helpful..If you want to learn more about Cloud Native, you can read JavaScript Cloud Native Development Cookbook..This book helps you learn the major concepts of cloud-native development faster by taking a recipe-based approach, where you can try out different solutions to understand the concepts.. More details