Kafka Streams API is a part of Kafka, it goes without saying that monitoring your application will require some monitoring of Kafka as well. Performance The consumer and producer performance is one of the fundamental performance concerns for a producer and consumer.   The Kafka data flow diagram What is lag For producers, we care mostly about how fast the producer is sending messages to the broker. Obviously, the higher the throughput, the better. For consumers, we’re also concerned with performance, or how fast we can read messages from a broker. we care about how much and how fast our producers can publish to a broker, and we simultaneously care about how quickly our consumers can read those messages from the broker. The difference between how fast the producers place records on the broker and when consumers read those messages is called consumer lag How to check consumer lag To check for consumer lag, Kafka provides a convenient command-line tool, kafka-consumer-groups.sh,...