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Firebase Realtime Database vs Solace PubSub+

Firebase Realtime Database logo

Firebase Realtime Database

Databases

Store and sync data in real-time across all clients

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: Firebase Realtime Database the no-cost Spark plan caps storage at 1 GB, downloads at 10 GB per month and simultaneous connections at 100; 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: Firebase Realtime Database covers Real-time Sync, 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 Firebase Realtime Database and Solace PubSub+ actually diverge.

Attributes where Firebase Realtime Database and Solace PubSub+ differ
AttributeFirebase Realtime DatabaseSolace PubSub+
Pricing modelfreemiumquote
PlatformsWeb, Ios, AndroidLinux, Docker, Kubernetes, Cloud, Hardware appliance
Founded2011Unknown

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 Firebase Realtime Database

  • Real-time Sync
  • Offline Support
  • JSON Storage
  • Security Rules
  • Data Validation
  • Multi-platform SDKs
  • Scalable
  • Firebase Auth

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.

Firebase Realtime Database

  • Syncing JSON application state between clients in real timenot Solace PubSub+
  • Backing mobile and web apps with offline capable data storagenot Solace PubSub+
  • Prototyping realtime features such as presence and chatnot 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 Firebase Realtime Database
  • An exchange or trading platform with a latency budget that needs the hardware appliance rather than a software brokernot Firebase Realtime Database
  • An airline distributing operational events to ground systems, aircraft and partner APIs over different protocolsnot Firebase Realtime Database
  • A manufacturer bridging factory MQTT telemetry into an enterprise Kafka estate without writing translation servicesnot Firebase Realtime Database

Where each one falls short

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

Firebase Realtime Database

  • The no-cost Spark plan caps storage at 1 GB, downloads at 10 GB per month and simultaneous connections at 100
  • The Spark plan does not support multiple databases in a project
  • Even on the paid Blaze plan simultaneous connections are capped at 200,000 per database
  • Billing is by data transferred out at $1 per GB plus $5 per GB stored, so chatty clients cost more than the data volume suggests

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

Firebase Realtime Database

Free
  • SparkFree
    • 1 GB data storage included
    • 10 GB per month data downloads included
    • No charges for usage within limits
  • Blaze$5/per_GB_per_month
    • Maintains Spark free allowances
    • Pay-as-you-go for usage exceeding limits
    • Billing applies to data stored and outbound network traffic

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 Firebase Realtime Database if

  • You need real-time sync.
  • You want to start without paying.
  • You work on Web, Ios, Android.
  • You also want offline support.
Firebase Realtime Database 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 Firebase Realtime Database or Solace PubSub+ better?
Neither clearly leads. Firebase Realtime Database 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, Firebase Realtime Database or Solace PubSub+?
Firebase Realtime Database starts at Free and Solace PubSub+ at Free.
Does Firebase Realtime Database or Solace PubSub+ run on more platforms?
Firebase Realtime Database runs on Web, Ios, Android. Solace PubSub+ runs on Linux, Docker, Kubernetes, Cloud, Hardware appliance.
Can I use Firebase Realtime Database for free?
Both have a free tier, so you can try either at no cost before committing.
What is Firebase Realtime Database best used for?
Firebase Realtime Database is most often used for syncing json application state between clients in real time, backing mobile and web apps with offline capable data storage, prototyping realtime features such as presence and chat. Of those, syncing json application state between clients in real time and backing mobile and web apps with offline capable data storage are not what Solace PubSub+ is typically brought in for.
What can Firebase Realtime Database do that Solace PubSub+ cannot?
Firebase Realtime Database covers Real-time Sync, Offline Support, JSON Storage, Security Rules. Solace PubSub+ covers Multi-protocol broker, Dynamic message routing, Hardware appliance, Event Portal.

Answered from the vendors’ own pages

Firebase Realtime Database: How much does Firebase Realtime Database cost?

Firebase Realtime Database offers a free Spark plan (1 GB storage, 10 GB/month downloads) and a pay-as-you-go Blaze plan. On Blaze, storage costs $5 per GB per month, evaluated daily, with no monthly minimum charges.

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.

Firebase Realtime Database: What is included in Firebase Realtime Database free tier?

The Spark plan includes 1 GB of data storage and 10 GB per month of data downloads at no cost. Usage within these limits incurs no charges, making it suitable for small projects and testing.

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.

Firebase Realtime Database: Does Firebase Realtime Database charge for denied or rejected operations?

Yes. Firebase charges for all traffic to and from the database on the Blaze plan, including operations denied by security rules, outbound network traffic at the session layer, and connection and encryption overhead from all operations.

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.

Firebase Realtime Database: Can I set a spending limit on Firebase Realtime Database?

Firebase offers budget alerts but does not cap spending automatically. Users must monitor their usage dashboard in the Firebase console to track connections, storage, downloads, and load metrics; a calculator is available for cost estimation.

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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