How does a consumer differ from a consumer group in Kafka?

In Kafka, a consumer is a separate client that reads messages from topics.

A consumer group is a group of such clients that collectively read data from a topic, distributing partitions among themselves for parallel processing.

Main differences:

• Consumer — a single consumer that reads all messages from assigned partitions.
• Consumer group allows scaling of consumption: each consumer in the group reads its part of the data, ensuring load balancing.

Thus, a consumer group provides horizontal scaling and fault tolerance in message processing.