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Databases · head to head

Cassandra vs Solace PubSub+

Cassandra logo

Cassandra

Databases

Manage massive amounts of data with linear scalability

From
Free
Rated
-
Full reviewWebsite
Solace PubSub+ logo

Solace PubSub+

Databases

Multi-protocol event broker sold as software, cloud service or a hardware appliance

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Cassandra no support for joins across tables; Solace PubSub+ no pricing is published at any tier, so evaluation requires a sales engagement before you can even judge whether it is in budget, and broker tier sizing determines cost in ways buyers frequently get wrong.
  • They diverge on capability: Cassandra covers Linear Scalability, Solace PubSub+ covers Multi-protocol broker.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Cassandra and Solace PubSub+ actually diverge.

Attributes where Cassandra and Solace PubSub+ differ
AttributeCassandraSolace PubSub+
Pricing modelUnknownquote
PlatformsLinux, macOS, Windows, Docker, KubernetesLinux, Docker, Kubernetes, Cloud, Hardware appliance
Founded2008Unknown

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 Cassandra

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

Only in Solace PubSub+

  • Multi-protocol broker
  • Dynamic message routing
  • Hardware appliance
  • Event Portal
  • Guaranteed delivery
  • Mission Control
  • Topic hierarchies and wildcards
  • Kafka and MQ bridging

What people use each for

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

Cassandra

  • Real-time applicationsnot Solace PubSub+
  • Content managementnot Solace PubSub+
  • User profilesnot Solace PubSub+
  • Mobile backendsnot Solace PubSub+
  • Cachingnot Solace PubSub+

Solace PubSub+

  • A bank building an event mesh across regions where a Java JMS application and an MQTT mobile client must share the same topic spacenot Cassandra
  • An exchange or trading platform with a latency budget that needs the hardware appliance rather than a software brokernot Cassandra
  • An airline distributing operational events to ground systems, aircraft and partner APIs over different protocolsnot Cassandra
  • A manufacturer bridging factory MQTT telemetry into an enterprise Kafka estate without writing translation servicesnot 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

Solace PubSub+

  • No pricing is published at any tier, so evaluation requires a sales engagement before you can even judge whether it is in budget, and broker tier sizing determines cost in ways buyers frequently get wrong.
  • The free Standard edition has hard capacity and support limits, which makes it useful for development but means any real deployment triggers a commercial negotiation.
  • The proprietary SMF protocol gives the best performance and feature coverage, so teams that lean on it acquire real switching costs even though open protocols are supported.
  • Operating a self-managed high availability broker pair with disaster recovery is a specialist task, and Solace expertise is scarce in the hiring market compared with Kafka skills.
  • Event Portal and Mission Control are licensed as part of platform packages, so the governance tooling that makes an event mesh manageable is not simply included with the broker.

Pricing, plan by plan

Cassandra

Free

No published plan breakdown. See the Cassandra review.

Solace PubSub+

Free
  • Software Event Broker StandardFree
    • Free for production within capacity limits
    • Single node, capped connections and queues
    • No vendor support
  • Solace Cloud$undefined/year
    • Managed brokers in tiers from ENT-250 to ENT-100K
    • Foundation, Accelerate and Scale platform packages
    • Fixed subscription or annual consumption drawdown
  • Software Enterprise self-managed$undefined/year
    • Deploy in your own Kubernetes, VMs or data centre
    • High availability and disaster recovery
    • Support with SLA
  • Hardware appliance$undefined/year
    • Purpose-built appliance with FPGA message offload
    • Deterministic low latency
    • Sold with support contract

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 Solace PubSub+ if

  • You need multi-protocol broker.
  • You want to start without paying.
  • You work on Linux, Docker, Kubernetes, Cloud, Hardware appliance.
  • You also want dynamic message routing.
Solace PubSub+ review

Questions people ask

Is Cassandra or Solace PubSub+ better?
Neither clearly leads. Cassandra starts at Free and Solace PubSub+ at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cassandra or Solace PubSub+?
Cassandra starts at Free and Solace PubSub+ at Free.
Does Cassandra or Solace PubSub+ run on more platforms?
Cassandra runs on Linux, macOS, Windows, Docker, Kubernetes. Solace PubSub+ runs on Linux, Docker, Kubernetes, Cloud, Hardware appliance.
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 Solace PubSub+ is typically brought in for.
What can Cassandra do that Solace PubSub+ cannot?
Cassandra covers Linear Scalability, Fault Tolerance, Multi-datacenter Replication, Tunable Consistency. Solace PubSub+ covers Multi-protocol broker, Dynamic message routing, Hardware appliance, Event Portal.

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
Solace PubSub+: Is there a free version of Solace?

Yes, the Standard edition of the software event broker is free for production within capacity limits, with no vendor support.

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
Solace PubSub+: Does Solace publish prices?

No. Cloud, software and appliance are all quoted, based on broker tier from ENT-250 to ENT-100K and licensing model.

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
Solace PubSub+: Why buy an appliance in 2026?

Deterministic low latency with message processing offloaded to hardware, which matters in capital markets and little elsewhere.

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
Solace PubSub+: Can it replace Kafka?

Not for log retention and stream reprocessing. It is stronger at multi-protocol routing and guaranteed delivery, and the two are often bridged.

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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