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Databases · head to head

Apache Kafka vs Cassandra

Apache Kafka logo

Apache Kafka

Databases

Open-source distributed event streaming platform

From
Free
Rated
-
Full reviewWebsite
Cassandra logo

Cassandra

Databases

Manage massive amounts of data with linear scalability

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Apache Kafka operationally heavy to self-host: brokers, storage, rebalancing and upgrades are a standing job, which is why managed Kafka is a large market; Cassandra no support for joins across tables
  • They diverge on capability: Apache Kafka covers Durable commit log, Cassandra covers Linear Scalability.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Apache Kafka and Cassandra actually diverge.

Attributes where Apache Kafka and Cassandra differ
AttributeApache KafkaCassandra
Pricing modelOpen source, no licence fee; managed services billed separatelyUnknown
PlatformsLinux, Windows, macOS, Self-hosted, DockerLinux, macOS, Windows, Docker, Kubernetes
FoundedUnknown2008

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Databases).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Apache Kafka

  • Durable commit log
  • Horizontal scale
  • Kafka Connect
  • Kafka Streams
  • Replication
  • Low latency

Only in Cassandra

  • Linear Scalability
  • Fault Tolerance
  • Multi-datacenter Replication
  • Tunable Consistency
  • CQL Query Language
  • Distributed Architecture
  • No Single Point of Failure
  • DataStax

What people use each for

The jobs each tool is most often brought in to do.

Apache Kafka

  • Moving events between services without point-to-point couplingnot Cassandra
  • Feeding analytics and warehouses from operational systems in near real timenot Cassandra
  • Replaying history to rebuild state after a consumer bugnot Cassandra
  • Buffering bursty producers ahead of slower downstream systemsnot Cassandra

Cassandra

  • Real-time applicationsnot Apache Kafka
  • Content managementnot Apache Kafka
  • User profilesnot Apache Kafka
  • Mobile backendsnot Apache Kafka
  • Cachingnot Apache Kafka

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Apache Kafka

  • Operationally heavy to self-host: brokers, storage, rebalancing and upgrades are a standing job, which is why managed Kafka is a large market
  • Overkill for straightforward job queues, where a simpler broker is easier to run and reason about
  • Ordering guarantees hold per partition, not per topic, and getting partitioning wrong is a common and expensive design mistake
  • The ecosystem is fragmented across the Apache project and vendor distributions, so documentation and tooling advice often assume a particular distribution

Cassandra

  • No support for joins across tables
  • No ACID transactions across multiple rows
  • Data model must be designed around query patterns upfront, making schema evolution difficult
  • Partition key misconfigurations can cause uneven data distribution and hotspots that degrade performance

Pricing, plan by plan

Apache Kafka

Free
  • Apache KafkaFree
    • Full platform
    • Kafka Connect
    • Kafka Streams

Cassandra

Free

No published plan breakdown. See the Cassandra review.

Which should you pick?

Choose Apache Kafka if

  • You need durable commit log.
  • You want to start without paying.
  • You work on Linux, Windows, macOS, Self-hosted, Docker.
  • You also want horizontal scale.
Apache Kafka review

Choose Cassandra if

  • You need linear scalability.
  • You want to start without paying.
  • You work on Linux, macOS, Windows, Docker, Kubernetes.
  • You also want fault tolerance.
Cassandra review

Questions people ask

Is Apache Kafka or Cassandra better?
Neither clearly leads. Apache Kafka starts at Free and Cassandra at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Apache Kafka or Cassandra?
Apache Kafka starts at Free and Cassandra at Free.
Does Apache Kafka or Cassandra run on more platforms?
Apache Kafka runs on Linux, Windows, macOS, Self-hosted, Docker. Cassandra runs on Linux, macOS, Windows, Docker, Kubernetes.
Can I use Apache Kafka for free?
Both have a free tier, so you can try either at no cost before committing.
What is Apache Kafka best used for?
Apache Kafka is most often used for moving events between services without point-to-point coupling, feeding analytics and warehouses from operational systems in near real time, replaying history to rebuild state after a consumer bug, buffering bursty producers ahead of slower downstream systems. Of those, moving events between services without point-to-point coupling and feeding analytics and warehouses from operational systems in near real time are not what Cassandra is typically brought in for.
What can Apache Kafka do that Cassandra cannot?
Apache Kafka covers Durable commit log, Horizontal scale, Kafka Connect, Kafka Streams. Cassandra covers Linear Scalability, Fault Tolerance, Multi-datacenter Replication, Tunable Consistency.

Answered from the vendors’ own pages

Apache Kafka: Is Apache Kafka free?

Yes. Kafka is open source under the Apache License v2 with no licence fee. Costs come from the infrastructure you run it on, or from a managed service such as Confluent Cloud.

Cassandra: Does Cassandra support joins between tables?

No. Cassandra does not support joins or foreign keys. The data model requires denormalization, meaning data must be duplicated across tables to support different query patterns.

Source
Apache Kafka: How is Kafka different from a message queue?

A queue usually removes a message once it is consumed. Kafka keeps an ordered, durable log, so consumers track their own position and history can be replayed — which is what makes rebuilding state after a bug possible.

Cassandra: Does Cassandra offer ACID transactions?

No. Cassandra provides only row-level atomicity and isolation, not full ACID transactions across multiple rows or tables. It uses lightweight transactions via Paxos for per-row compare-and-set operations.

Source
Apache Kafka: Who uses Kafka?

The project reports use by more than 80% of the Fortune 100, with over 5 million lifetime downloads.

Cassandra: What programming languages can connect to Cassandra?

Cassandra supports official drivers for multiple languages including Python, Java, Node.js, and Go, allowing applications to communicate via the native Cassandra protocol.

Source
Apache Kafka: Do I need to run Kafka myself?

No. Self-hosting is the operationally expensive option; managed services such as Confluent Cloud run the brokers for you and bill on throughput and storage instead.

Cassandra: Can I deploy Cassandra in the cloud?

Yes. Cassandra can run on any cloud platform (AWS, Google Cloud, Azure) via Docker, virtual machines, or managed services like DataStax Astra DB, which provides a fully managed DBaaS option.

Source
Cassandra: Does Cassandra have a free option?

The open source Apache Cassandra is free. DataStax also offers Astra DB with a free tier providing up to 25GB storage and 25 million read/write operations per month.

Source
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