Amazon SQS vs Kafka: What are the differences?

Amazon SQS and Kafka are both messaging platforms that allow for real-time, asynchronous communication between systems. However, there are key differences between the two.

1. Architecture: Amazon SQS is a fully managed, pull-based system, while Kafka is a distributed, pub-sub system. SQS uses a message broker architecture with a central service managing the message queue, while Kafka uses a distributed log architecture where messages are stored in a distributed commit log.

2. Scalability: SQS is highly scalable and can handle millions of messages per second, but it has limitations on message size and retention time. On the other hand, Kafka is designed for high-throughput, fault-tolerant, and horizontally scalable streaming, making it suitable for handling large volumes of data and providing longer retention periods.

3. Message Persistence: SQS guarantees message persistence, storing messages in multiple data centers for durability. Kafka also provides persistence through its replicated log, but it allows users to configure the retention period and disk space used for data storage.

4. Message Delivery: SQS ensures at-least-once delivery of messages, providing exactly-once delivery semantics using deduplication mechanisms. Kafka guarantees at-least-once message delivery and can achieve exactly-once semantics through idempotent message writes and transactional support.

5. Consumer Groups: Kafka supports the concept of consumer groups, where multiple consumers can independently read from different partitions of a topic. This allows for load balancing and fault tolerance. SQS, on the other hand, does not have built-in support for consumer groups and requires separate queues for each consumer.

6. Integration: Amazon SQS is tightly integrated with other AWS services, making it easy to incorporate into an AWS-based architecture. Kafka has a broader integration ecosystem, with connectors available for various data systems and frameworks.

In summary, the key differences between Amazon SQS and Kafka lie in their architecture, scalability, message persistence, delivery guarantees, support for consumer groups, and integration capabilities. It is important to consider these differences when choosing a messaging platform for your specific use case.