Is Cassandra or Postgres better?

Neither clearly leads. Cassandra starts at Free and Postgres at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.

Which is cheaper, Cassandra or Postgres?

Cassandra starts at Free and Postgres at Free.

Does Cassandra or Postgres run on more platforms?

Cassandra runs on Linux, macOS, Windows, Docker, Kubernetes. Postgres runs on Linux, Windows, Macos, Docker.

Can I use Cassandra for free?

Both have a free tier, so you can try either at no cost before committing.

What is Cassandra best used for?

Cassandra is most often used for real-time applications, content management, user profiles, mobile backends. Of those, real-time applications and content management are not what Postgres is typically brought in for.

What can Cassandra do that Postgres cannot?

Cassandra covers Linear Scalability, Fault Tolerance, Multi-datacenter Replication, Tunable Consistency. Postgres covers ACID compliance, Complex queries, Foreign keys, Triggers.

Databases · head to head

Cassandra vs Postgres

Cassandra

Databases

Manage massive amounts of data with linear scalability

From: Free
Rated: -

Full review Website

Postgres

Technology

The world's most advanced open source database

From: Free
Rated: -

Full review Website

The short version

Each has a real cost: Cassandra no support for joins across tables; Postgres each major version is supported for only 5 years after its initial release, after which it is end-of-life
They diverge on capability: Cassandra covers Linear Scalability, Postgres covers ACID compliance.
Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Cassandra and Postgres actually diverge.

Attributes where Cassandra and Postgres differ
Attribute	Cassandra	Postgres
Pricing model	Unknown	open-source
Platforms	Linux, macOS, Windows, Docker, Kubernetes	Linux, Windows, Macos, Docker
Category	Databases	Technology
Founded	2008	1996

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

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 Cassandra

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

Only in Postgres

ACID compliance
Complex queries
Foreign keys
Triggers
Views
Stored procedures
JSON/JSONB support
Full-text search

What people use each for

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

Cassandra

Real-time applicationsnot Postgres
Content managementnot Postgres
User profilesnot Postgres
Mobile backendsnot Postgres
Cachingnot Postgres

Postgres

Running a general purpose relational database for applicationsnot Cassandra
Self-hosting an open source SQL database with no licence feenot Cassandra
Workloads needing extensions, JSON and full text search in one enginenot Cassandra

Where each one falls short

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

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

Postgres

Each major version is supported for only 5 years after its initial release, after which it is end-of-life
Major version upgrades break on-disk compatibility and require a full dump and reload or the pg_upgrade tool
New major versions ship about once a year, so staying supported means a disruptive upgrade cycle
Minor releases contain only frequently-encountered bug fixes, low-risk fixes, security issues and data corruption fixes, so feature gaps are not addressed within a major version
There is no vendor SLA; commercial support must be bought separately from third party professional services listed by the project

Pricing, plan by plan

Cassandra

Free

No published plan breakdown. See the Cassandra review.

Postgres

Free

Community EditionFree
- Full database features
- No limitations
- Community support

Which should you pick?

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

Choose Postgres if

You need acid compliance.
You want to start without paying.
You work on Linux, Windows, Macos, Docker.
You also want complex queries.

Postgres review

Questions people ask

Is Cassandra or Postgres better?: Neither clearly leads. Cassandra starts at Free and Postgres at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cassandra or Postgres?: Cassandra starts at Free and Postgres at Free.
Does Cassandra or Postgres run on more platforms?: Cassandra runs on Linux, macOS, Windows, Docker, Kubernetes. Postgres runs on Linux, Windows, Macos, Docker.
Can I use Cassandra for free?: Both have a free tier, so you can try either at no cost before committing.
What is Cassandra best used for?: Cassandra is most often used for real-time applications, content management, user profiles, mobile backends. Of those, real-time applications and content management are not what Postgres is typically brought in for.
What can Cassandra do that Postgres cannot?: Cassandra covers Linear Scalability, Fault Tolerance, Multi-datacenter Replication, Tunable Consistency. Postgres covers ACID compliance, Complex queries, Foreign keys, Triggers.

Answered from the vendors’ own pages

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

Postgres: How much does PostgreSQL cost to use?

PostgreSQL is completely free to download, install, and use. No licensing fees, subscription costs, or per-seat charges apply. The database is open source under the PostgreSQL License. Source: https://www.postgresql.org

Source

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

Postgres: Are there commercial PostgreSQL support options available?

Official PostgreSQL (the project) is free. Commercial PostgreSQL services such as hosting, professional support, training, and managed database services are offered by third-party vendors, not the PostgreSQL project itself. Source: https://www.postgresql.org

Source

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

Postgres: Do I need a license to use PostgreSQL commercially?

No. PostgreSQL is open source under the PostgreSQL License, which permits free commercial use without royalties, licensing fees, or support obligations. Source: https://www.postgresql.org

Source

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

Cassandra vs Postgres

Cassandra

Postgres

The short version

Where they differ

What each one covers

Only in Cassandra

Only in Postgres

What people use each for

Cassandra

Postgres

Where each one falls short

Cassandra

Postgres

Pricing, plan by plan

Cassandra

Postgres

Which should you pick?

Choose Cassandra if

Choose Postgres if

Questions people ask

Answered from the vendors’ own pages

Related pages

More on Cassandra

More on Postgres

Keep looking

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