What is Kafka Streams? Kafka Streams is a client library for building real-time applications and microservices. It enables organizations to act on data as it arrives.

What is Kafka Streams?

Published September 2023

Traditional batch processing systems, albeit effective for fixed datasets, are often ill-suited for real-time, high-throughput scenarios. Kafka Streams enables organizations to act on data as it arrives, making it particularly useful for applications that require immediate response.

Kafka Streams is a client library for building real-time applications and microservices. It’s a part of the larger Apache Kafka distributed event streaming platform. The Kafka Streams library simplifies the process of reading data from Kafka topics, processing it, and then writing the processed data back to another Kafka topic or external system.

At its core, Kafka Streams operates by processing each event individually or in small groups. This approach provides real-time processing as opposed to traditional batch processing systems. 

When to Use Kafka Streams

Real-Time Analytics

Kafka Streams is well-suited for when you need to perform analytics on data as it arrives. Imagine an e-commerce platform that tracks user behavior in real-time to offer personalized recommendations. Kafka Streams can consume events like clicks, searches, and purchases, analyze them instantly, and update the recommendations in real-time.

Event Sourcing

In microservices architectures, maintaining the state can be a complex task. Kafka Streams can serve as the backbone for an event sourcing system, capturing the state changes as a series of immutable events. This can simplify the architecture by enabling services to reconstruct their state from these events.

Data Aggregation

Kafka Streams is excellent for aggregating data from multiple sources and funneling it into a centralized data lake or database. For instance, it can aggregate logs from different services and store them in a format that is easier for debugging and monitoring.

Stream-Table Joins

If your application needs to enrich a data stream with static data, Kafka Streams can do this efficiently through stream-table joins. For example, you could enrich a stream of sales transactions with customer information stored in a table.

Alternatives to Kafka Streams

While Kafka Streams is robust and feature-rich, it’s not a one-size-fits-all solution. Here are some alternatives:

Apache Flink

Apache Flink is another stream-processing framework that excels in advanced windowing and stateful computations. It can run on top of various storage systems, including Kafka.

Apache Storm

Storm offers real-time computation capabilities but leans towards simpler use-cases compared to Kafka Streams and Flink. It’s easy to set up and offers excellent performance. Storm is suitable for simpler real-time analytics applications.

Cloud-Based Solutions

Services like AWS Kinesis, Google Cloud Dataflow, and Azure Stream Analytics offer managed streaming solutions that may be easier to set up and scale. This is especially the case if you’re already committed to a specific cloud ecosystem.

Apache Streams is also available as a managed service through companies like Dattell.  Dattell offers fully managed Kafka in your environment

Drawbacks of Using Kafka Streams


Kafka Streams requires a good understanding of the Kafka ecosystem. The learning curve can be steep, especially for teams not already familiar with Kafka.

Resource Intensive

Although Kafka Streams is designed to scale, it can be resource-intensive, especially for larger implementations. This can increase operational overhead in terms of both hardware and management.

Limited Advanced Features

While Kafka Streams is powerful, it lacks some of the advanced windowing and state management features that specialized frameworks like Flink offer.

Other Technologies to Consider

Besides the direct alternatives to Kafka Streams, there are other technologies that could play a role in your data architecture:

Message Queues

Technologies like RabbitMQ or ActiveMQ can offer queue-based data handling. However, they lack the stream-processing capabilities of Kafka Streams.

You can read our detailed comparison of RabbitMQ and Kafka here.

Batch Processing Systems

For non-real-time needs, traditional batch processing systems like Apache Hadoop can be more appropriate and resource-efficient.

Final Thoughts on Kafka Streams

Kafka Streams helps organizations turn their data into a manageable, actionable flow of insights.

Before diving into Kafka Streams, it’s wise to evaluate your specific needs and consider alternatives. Kafka Streams is a powerful tool, but it’s part of a larger data architecture toolkit. Understanding when to use it—and when not to—is key to optimizing your data operations effectively.

Have Kafka Questions?

Managed Kafka on your environment with 24/ 7 support.

Consulting support to implement, troubleshoot,
and optimize Kafka.

Schedule a call with a Kafka solution architect.

Published by

Dattell - Kafka & Elasticsearch Support

Benefit from the experience of our Kafka, Pulsar, Elasticsearch, and OpenSearch expert services to help your team deploy and maintain high-performance platforms that scale. We support Kafka, Elasticsearch, and OpenSearch both on-prem and in the cloud, whether on stand alone clusters or running within Kubernetes. We’ve saved our clients $100M+ over the past six years. Without our guidance companies tend to overspend on hardware or purchase unnecessary licenses. We typically save clients multiples more money than our fees cost in addition to building, optimizing, and supporting fault-tolerant, highly available architectures.