We are using this custom serializer `RollupEventSerializer` by setting it as a config over here https://github.com/cngupte123/blueflood/blob/20d08d37c6f3b928fd87608379afd147711edec5/blueflood-kafka/kafka.conf#L2. So the modularity of supporting future custom serializers is already supported. I missed to change this config in the kafka config used in tests https://github.com/cngupte123/blueflood/blob/20d08d37c6f3b928fd87608379afd147711edec5/blueflood-kafka/src/test/resources/testKafka.conf#L2 which might have been confusing.