Apache Kafka is getting used as an event backbone in new organizations every day. We would love to send every byte of data through the event bus. Like traditional REST APIs, a contract-first approach is very useful when designing event-driven architectures. In the case of asynchronous APIs, we have the AsyncAPI specification to document the endpoints where the schema of the records become the main part of the contract payload. Microcks allows us to deploy a testing and mocking platform to have a unified view of the endpoints to speed-up application delivery. In this session we will: - Go over the evolution of API specifications - Review the approach for contract-first design with Apache Kafka - Introduce the AsyncAPI specification - Take an overview of an implementation example for automated mocking and testing