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Databases · head to head

Apache Kafka vs PostgreSQL

Apache Kafka logo

Apache Kafka

Databases

Open-source distributed event streaming platform

From
Free
Rated
-
Full reviewWebsite
PostgreSQL logo

PostgreSQL

Databases

The world's most advanced open source relational database

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; PostgreSQL requires manual scaling across multiple machines for very large deployments
  • They diverge on capability: Apache Kafka covers Durable commit log, PostgreSQL covers ACID Compliance.

Where they differ

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

Attributes where Apache Kafka and PostgreSQL differ
AttributeApache KafkaPostgreSQL
Pricing modelOpen source, no licence fee; managed services billed separatelyUnknown
PlatformsLinux, Windows, macOS, Self-hosted, DockerLinux, Windows, macOS, BSD, Unix
FoundedUnknown1996

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
  • Low latency

Only in PostgreSQL

  • ACID Compliance
  • JSON/JSONB Support
  • Full-text Search
  • Extensibility
  • Advanced Indexing
  • Partitioning
  • pgAdmin
  • DBeaver

Both cover

  • Replication

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 PostgreSQL
  • Feeding analytics and warehouses from operational systems in near real timenot PostgreSQL
  • Replaying history to rebuild state after a consumer bugnot PostgreSQL
  • Buffering bursty producers ahead of slower downstream systemsnot PostgreSQL

PostgreSQL

  • Transaction processingnot Apache Kafka
  • Data storagenot Apache Kafka
  • Application backendnot Apache Kafka
  • Reportingnot Apache Kafka
  • Data analyticsnot 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

PostgreSQL

  • Requires manual scaling across multiple machines for very large deployments
  • Performance tuning requires deep knowledge of database internals
  • No built-in graphical admin interface; command-line tools are primary method

Pricing, plan by plan

Apache Kafka

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

PostgreSQL

Free

No published plan breakdown. See the PostgreSQL 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 PostgreSQL if

  • You need acid compliance.
  • You want to start without paying.
  • You work on Linux, Windows, macOS, BSD, Unix.
  • You also want json/jsonb support.
PostgreSQL review

Questions people ask

Is Apache Kafka or PostgreSQL better?
Neither clearly leads. Apache Kafka starts at Free and PostgreSQL at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Apache Kafka or PostgreSQL?
Apache Kafka starts at Free and PostgreSQL at Free.
Does Apache Kafka or PostgreSQL run on more platforms?
Apache Kafka runs on Linux, Windows, macOS, Self-hosted, Docker. PostgreSQL runs on Linux, Windows, macOS, BSD, Unix.
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 PostgreSQL is typically brought in for.
What can Apache Kafka do that PostgreSQL cannot?
Apache Kafka covers Durable commit log, Horizontal scale, Kafka Connect, Kafka Streams. PostgreSQL covers ACID Compliance, JSON/JSONB Support, Full-text Search, Extensibility. Both handle Replication.

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.

PostgreSQL: Is PostgreSQL completely free?

Yes. PostgreSQL is completely free and open source with no licensing fees or restrictions on use.

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.

PostgreSQL: What platforms does PostgreSQL run on?

PostgreSQL runs on all major operating systems including Linux, Windows, macOS, BSD, and commercial Unix variants, and has been proven highly scalable managing terabytes to petabytes of data.

Source
Apache Kafka: Who uses Kafka?

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

PostgreSQL: What procedural languages are supported?

PostgreSQL supports stored functions and procedures in multiple languages including PL/pgSQL, Perl, Python, Tcl, Java, JavaScript, R, and Rust.

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.

PostgreSQL: What is ACID compliance in PostgreSQL?

PostgreSQL has been ACID-compliant since 2001, ensuring data integrity through atomicity, consistency, isolation, and durability guarantees for all transactions.

Source
PostgreSQL: Does PostgreSQL support JSON data?

Yes. PostgreSQL supports JSON and JSONB data types for storing and querying JSON documents, along with XML and other document formats.

Source
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