I have a spring webapp that communicates with external service over kafka. IS it possible to somehow test contract between those services?
Yes you can. Spring Cloud Contract supports CDC with messaging. If you're using Spring Cloud Stream - the work to be done is trivial. If not then you'll have to implement your own as presented in this issue - Spring Cloud Contract and plain Spring AMQP . Summing it up it's enough for both consumer and producer to implement a custom org.springframework.cloud.contract.verifier.messaging.MessageVerifier
bean that will be responsible for receiving and sending of messages via Kafka