Introduction
Contract first application development is not limited to synchronized RESTFul API calls. With the adoption of event-driven architecture, more developers are demanding a way to set up contracts between these asynchronous event publishers and consumers. Sharing what data format that each subscriber is consuming, what data format is used from the event publisher, in a way OpenAPI standards is going to be very helpful.
But in the asynchronous world, it is ever more complex, not only do you need to be caring about the data schema, there are different protocols, serializing, deserializing mechanisms, and various support libraries. In fact, there are talks on AsyncAPI. But I am going to show you that what can be done today, is to use ONE of the most commonly used solutions in building EDA, “Kafka”. And show how to do Contract First Application Development using Camel + Apicurio Registry.