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Spark vs. Kafka: 5 Key Differences and How to Choose

Meni Shmueli

Performance Researcher & Software Architect, Intel Granulate

What Is Apache Spark?  

Apache Spark is an open-source, distributed computing system designed for processing large volumes of data quickly and efficiently. It was developed in response to the limitations of the Hadoop MapReduce computing model, providing a more flexible and user-friendly alternative for big data processing.

Spark is built on top of the Hadoop Distributed File System (HDFS) and can also work with other storage systems. It offers a rich set of APIs in various programming languages. The core of Spark is the Resilient Distributed Dataset (RDD), an immutable distributed collection of objects. RDDs can be cached in memory, allowing Spark to perform iterative computations much faster than disk-based systems.

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Spark’s key features include support for machine learning (MLlib), graph processing (GraphX), stream processing (Structured Streaming), and SQL querying (Spark SQL). Additionally, it offers a built-in interactive shell for Scala and Python, making it easier to develop and test code.

What Is Apache Kafka?  

Apache Kafka is an open-source, distributed streaming platform designed for building real-time data pipelines and streaming applications. It was initially developed at LinkedIn and later became a part of the Apache Software Foundation. Kafka enables high-throughput, fault-tolerant, and scalable messaging between producers and consumers, ensuring efficient handling of massive volumes of data.

Kafka operates on a publish-subscribe model, wherein producers publish messages to topics, while consumers subscribe to topics and process the messages. It maintains a distributed, append-only log for each topic, providing strong durability and low-latency performance.

Key features of Apache Kafka include horizontal scalability, fault tolerance, strong durability, and built-in stream processing capabilities. It is widely used in various industries for real-time analytics, log aggregation, event-driven architectures, and data integration scenarios.

In this article:

Apache Spark vs. Kafka: 5 Key Differences  

1. Extract, Transform, and Load (ETL) Tasks

  • Spark excels at ETL tasks due to its ability to perform complex data transformations, filter, aggregate, and join operations on large datasets. It has native support for various data sources and formats, and can read from and write to HDFS, S3, Cassandra, HBase, and other storage systems. Spark’s DataFrame API and Spark SQL provide high-level abstractions for working with structured data, while the core RDD API caters to unstructured or semi-structured data.
  • Kafka is not primarily an ETL tool but can be used in conjunction with other tools to build ETL pipelines. It serves as a high-throughput messaging system, facilitating data ingestion and transportation between systems. Kafka Connect, an add-on component, enables integration with various data sources and sinks, while Kafka Streams and KSQL provide lightweight stream processing capabilities for simple transformations, filtering, and aggregations.

2. Latency  

  • Spark is a batch processing system that can handle micro-batches, enabling near-real-time data processing. However, it has relatively higher latency compared to Kafka due to the overhead associated with scheduling and executing tasks. Spark Streaming, which processes data in micro-batches, provides lower latency than traditional batch processing but is still not as low as Kafka Streams.
  • Kafka is designed for low-latency, real-time data streaming. It ensures that messages are written and read with minimal delays, making it suitable for scenarios where real-time processing is critical. Kafka Streams, a lightweight stream processing library, allows for event-by-event processing, further reducing latency.

3. Memory Management

  • Spark uses in-memory processing, storing intermediate data in memory to avoid expensive disk I/O operations. This accelerates iterative algorithms and complex data processing tasks. However, Spark’s memory usage can be high, potentially causing issues in resource-constrained environments. Users can configure memory settings, such as caching strategies and storage levels, to balance performance and resource consumption.
  • Kafka is optimized for efficient disk storage and low-latency message transfer. It uses the underlying file system cache to buffer messages in memory, ensuring fast read and write operations. Kafka’s memory usage is generally lower than Spark’s since it doesn’t store intermediate processing results in memory.

4. Recovery

  • Spark ensures fault tolerance through data replication and lineage information. RDDs, the core data structure, can be recomputed in case of node failures, using lineage information. Additionally, Spark allows users to persist RDDs and DataFrames with different replication factors, ensuring data redundancy. Spark can also recover from application failures by checkpointing the metadata and streaming data at user-defined intervals.
  • Kafka provides built-in fault tolerance through data replication across multiple brokers within a cluster. It stores messages in a distributed, partitioned, and replicated log, ensuring data durability and redundancy. In case of a broker failure, Kafka can automatically elect a new leader for the affected partitions, ensuring continuous availability. 

5. Supported Languages

  • Spark offers APIs for multiple programming languages, including Scala, Java, Python, and R. This flexibility allows developers to choose the language that best suits their needs and skillsets. Additionally, Spark provides interactive shells for Scala and Python, facilitating rapid development and testing of code.
  • Kafka‘s core APIs (producer, consumer, and admin) are primarily available in Java and Scala. However, there are community-supported clients for other languages, such as Python, Go, and C++.

Learn more in our detailed guide to Spark performance 

Spark vs. Kafka: How to Choose? 

Apache Spark and Apache Kafka are both open-source, distributed computing systems, but they serve different purposes and excel in different use cases. To choose between them, you should consider your specific requirements and the problems you’re trying to solve. 

Use Cases and Strengths of Apache Spark

Use Cases:

  • Data processing and ETL (Extract, Transform, Load) operations
  • Machine learning and AI with MLlib and GraphX
  • SQL querying with Spark SQL
  • Graph processing with GraphX
  • Stream processing with Structured Streaming or DStreams (micro-batch processing)


  • Supports a wide range of data processing tasks
  • High-level APIs for Scala, Java, Python, and R
  • In-memory processing for faster performance
  • Fault-tolerant with data replication and lineage information
  • Supports SQL, machine learning, and graph processing

Use Cases and Strengths of Apache Kafka

Use Cases:

  • Messaging and event streaming
  • Log and event data aggregation
  • Real-time analytics and monitoring
  • Decoupling of data streams and systems
  • Building event-driven applications and microservices


  • High-throughput and low-latency data streaming
  • Distributed, fault-tolerant, and scalable architecture
  • Built-in data durability with data replication
  • Supports publish-subscribe and queue-based messaging patterns
  • Strong ecosystem with Kafka Connect (for data integration) and Kafka Streams (for stream processing)

How to Choose

If you need a system for large-scale data processing, querying, and machine learning workloads, Apache Spark is likely the better choice.

If you require a high-throughput, low-latency, and scalable real-time data streaming platform for messaging, event-driven applications, or real-time analytics, Apache Kafka is the right choice.

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It’s worth noting that Apache Spark and Apache Kafka can be used together in a complementary manner. You can use Kafka as the real-time data streaming platform to collect and store events, while Spark can be used to process and analyze the data. Spark’s Structured Streaming API can also consume data directly from Kafka, providing an integrated solution for real-time data processing and analytics.

Learn more in our detailed guide to:
Spark streaming
Apache spark tutorial
Spark on AWS

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