Kafka vs RabbitMQ

Kafka and RabbitMQ are the two Java frameworks used in software programming. In this article, the frameworks of the two features are compared.

1. Distribution and parallelism

Kafka distributes consumers by topic partitions. Each consumer from the group is assigned to one partition. The partition mechanism can be used to send different sets of messages by business keys (e.g., location or user ID).

In RabbitMQ, the number of consumers can be scaled out, which means that each queue instance will have many consumers. This makes message processing spread to all active consumers, but a message can only be processed once.

2. High Availability

Both frameworks are highly available. However, Kafka has an edge as it uses Zookeeper to manage the state of the cluster. A Zookeeper keeps track of the status of Kafka cluster nodes, Kafka topics, partitions, etc.

3. Performance

Kafka supports the strength of sequential disk I/O and requires less hardware. This leads to a high throughput - several millions of messages per second - with a tiny number of nodes.

RabbitMQ can also process a million messages per second but it requires above 30 nodes.

4. Replication

Kafka has replicated the broker by design. This means that if the master broker is down, all the work is automatically passed to another broker which has a full replica of the dead one; hence, no message is ever lost.

In RabbitMQ queues aren’t automatically replicable.

5. Message ordering

Since Kafka has partitions, messages can be received by ordering. This can’t be achieved in RabbitMQ.

6. Multi subscriber

In Kafka, a message can be subscribed by multiple consumers.

In RabbitMQ, a message can only be consumed once, and once it is consumed, the message disappears and becomes inaccessible.

7. Message protocols

Kafka supports primitives (int8, int16, int32, int64, string, arrays) and binary messages.

RabbitMQ supports almost all standard queue protocols like AMQP, STOMP, HTTP, and MQTT.

8. Message lifetime

Since Kafka is a log, messages are always there. RabbitMQ is a queue that removes messages once they are consumed.

9. Message acknowledgment

Both frameworks give confirmation to the producer when messages arrive in the topic/queue.

10. Flexible routing to a topic/queue

In Kafka, a message is sent to the topic by a key; however, in RabbitMQ, there are more options (e.g., sending a message using regular expressions).