Kafka fundamentals

Kafka fundamentals in one place — topics, partitions, producers, consumers, brokers, replication and KRaft mode. The core concepts behind Apache Kafka.

Learn the core concepts that power Apache Kafka. This guide covers everything you need to understand how Kafka works under the hood.

Learning path

Work through these topics in order to build a solid foundation:

1. Core concepts

• What are Kafka topics? - learn about topics, partitions, and offsets
• Kafka producers - how applications send data to Kafka
• Kafka consumers - how applications read data from Kafka

2. Advanced concepts

• Consumer groups and offsets - understanding consumer coordination
• Kafka brokers - the servers that make up a Kafka cluster
• Topic replication - how Kafka ensures data durability

3. Infrastructure

• ZooKeeper - Kafka's coordination service (legacy)
• KRaft mode - Kafka without ZooKeeper (modern approach)

What you'll learn

After completing this section, you'll have a deep understanding of:

• Data flow: how messages move through Kafka
• Scalability: how Kafka handles millions of messages
• Reliability: how Kafka ensures no data loss
• Architecture: how all components work together

Next steps

• Start with Kafka topics to understand the foundation of how Kafka organizes data
• Learn how producers write data to see how events get into Kafka
• Learn how consumers read data to understand the other side of the pipeline