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Databases · head to head

CosmosDB vs Solace PubSub+

CosmosDB logo

CosmosDB

Databases

Globally distributed, multi-model database service from Azure

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: CosmosDB autoscale provisioned throughput enforces a minimum of 1,000 RU/s, billed hourly whether or not the database is used; 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: CosmosDB covers Global Distribution, 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 CosmosDB and Solace PubSub+ actually diverge.

Attributes where CosmosDB and Solace PubSub+ differ
AttributeCosmosDBSolace PubSub+
Pricing modelusage-basedquote
PlatformsWeb, AzureLinux, Docker, Kubernetes, Cloud, Hardware appliance
Founded1975Unknown

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 CosmosDB

  • Global Distribution
  • Multi-model APIs
  • Elastic Scaling
  • Five Consistency Levels
  • SLA-backed Latency
  • Automatic Indexing
  • Serverless
  • Azure Functions

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.

CosmosDB

  • Running a globally distributed multi model database on Azurenot Solace PubSub+
  • Serving low latency reads and writes from multiple Azure regionsnot Solace PubSub+
  • Storing document, key value and graph data behind a managed servicenot 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 CosmosDB
  • An exchange or trading platform with a latency budget that needs the hardware appliance rather than a software brokernot CosmosDB
  • An airline distributing operational events to ground systems, aircraft and partner APIs over different protocolsnot CosmosDB
  • A manufacturer bridging factory MQTT telemetry into an enterprise Kafka estate without writing translation servicesnot CosmosDB

Where each one falls short

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

CosmosDB

  • Autoscale provisioned throughput enforces a minimum of 1,000 RU/s, billed hourly whether or not the database is used
  • Provisioned throughput is charged in every region the account is replicated to, so multi region accounts multiply the RU bill
  • Storage charges cover data, indexes and backups in each replicated region
  • Egress out of Azure and between regions is charged, though ingress is free
  • The free allowance is one account per Azure subscription, limited to 1,000 RU/s and 25 GB
  • RU/s rates vary by region and are only shown through the pricing calculator rather than a flat published rate

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

CosmosDB

Free
  • Free TierFree
    • 1000 RU/s
    • 25GB storage
    • First 12 months
  • ServerlessFree
    • Pay per request
    • Auto-scaling
    • Event-driven workloads

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 CosmosDB if

  • You need global distribution.
  • You want to start without paying.
  • You work on Web, Azure.
  • You also want multi-model apis.
CosmosDB 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 CosmosDB or Solace PubSub+ better?
Neither clearly leads. CosmosDB 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, CosmosDB or Solace PubSub+?
CosmosDB starts at Free and Solace PubSub+ at Free.
Does CosmosDB or Solace PubSub+ run on more platforms?
CosmosDB runs on Web, Azure. Solace PubSub+ runs on Linux, Docker, Kubernetes, Cloud, Hardware appliance.
Can I use CosmosDB for free?
Both have a free tier, so you can try either at no cost before committing.
What is CosmosDB best used for?
CosmosDB is most often used for running a globally distributed multi model database on azure, serving low latency reads and writes from multiple azure regions, storing document, key value and graph data behind a managed service. Of those, running a globally distributed multi model database on azure and serving low latency reads and writes from multiple azure regions are not what Solace PubSub+ is typically brought in for.
What can CosmosDB do that Solace PubSub+ cannot?
CosmosDB covers Global Distribution, Multi-model APIs, Elastic Scaling, Five Consistency Levels. Solace PubSub+ covers Multi-protocol broker, Dynamic message routing, Hardware appliance, Event Portal.

Answered from the vendors’ own pages

CosmosDB: Is there a free tier for Azure Cosmos DB?

Yes, Cosmos DB offers a free tier with 1,000 RU/s of throughput and 25 GB of storage per month for the lifetime of the account, available to new accounts.

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.

CosmosDB: How is Cosmos DB priced after the free tier?

Cosmos DB uses three billing models: provisioned throughput billed per request unit per second, vCore pricing for certain APIs, or serverless consumption pricing where you pay only for requests processed. Reserved capacity offers 20% discount for one year or 30% for three years.

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.

CosmosDB: Can I change my pricing model after choosing one?

No. Once you select a compute pricing model and API, they cannot be changed. This choice is permanent for that database.

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.

CosmosDB: Is there a trial period for Cosmos DB beyond the free tier?

Azure offers a 30-day free trial account for all Azure services. Additionally, Azure AI customers may be eligible for a 90-day free Cosmos DB subscription through the Azure AI Advantage program.

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.

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