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Gokulnath P
Gokulnath P

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Kafka Fundamentals: A quick look at the basic building blocks

So what’s Kafka, anyway? Kafka is a super-fast, reliable tool for moving messages (events) between apps and services. Instead of sending data directly (like a phone call), services share what’s happening through Kafka — almost like posting messages on a community board. Others can check those messages whenever they want.

This setup lets lots of microservices talk with each other in a flexible, reliable way — making your app easier to build and scale without all the tight connections that can cause problems.

Let’s start by breaking down each building block of Kafka to see how they help everything communicate behind the scenes.

Messages / Events

Messages, sometimes called events, are like little notes that one service sends to another. They carry data, along with some extra info like when the message was created. They also have something called keys — we’ll explain how keys help group messages later. The important thing is that once a message is sent, it can’t be changed — just like sending a letter in the mail. This helps keep a clear and reliable record of what happened.

Kafka Message

Topic

Think of a topic like a folder that groups together similar events. Producers send their messages to a topic, and consumers subscribe to the topics they care about to get those events.

Kafka Topic

Broker

A broker is a server that manages the event streaming behind the scenes. It’s responsible for receiving messages, storing them safely, and then sending them to other services when they ask for them.

Kafka Broker

Cluster

A Kafka cluster is created by running multiple brokers together. The idea is that if one broker stops working, the others can keep everything running without any problems, so the event streaming never stops.

Kafka Cluster

Producer

A producer is an app or client that sends messages. It connects to the Kafka cluster and sends its messages to a specific topic.

Kafka Producer

Consumer

A consumer is an app or client that reads messages. It subscribes to one or more topics and pulls messages from the Kafka cluster to process or use them.

Kafka Consumer


Together, these building blocks form the heart of Kafka’s messaging system, letting different parts of your application communicate smoothly and reliably.

In future blogs, we’ll dive deeper into Kafka topics like partitions, consumer groups, offsets, and replication to get the full picture of how Kafka works in production. This way, you’ll build a strong foundation and be ready to use Kafka effectively in your own projects.

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