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Databases · head to head

Solace PubSub+ vs Spacelift

Solace PubSub+ logo

Solace PubSub+

Databases

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

From
Free
Free plan
Yes
Visit Solace PubSub+Full review
Spacelift logo

Spacelift

Developer Tools

Infrastructure-as-code orchestration for Terraform, OpenTofu, Pulumi and Kubernetes

From
Free
Free plan
Yes
Visit SpaceliftFull review

The short version

  • Both are free.
  • Only Solace PubSub+ lists dynamic message routing; only Spacelift lists policy as code.
  • Where Spacelift falls short: three of the five tiers are quote-only, so a shortlist cannot be costed without entering a sales process with each vendor on it.
  • Prices and features on this page were last checked on 31 August 2026.

Where they differ

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

Attributes where Solace PubSub+ and Spacelift differ
AttributeSolace PubSub+Spacelift
Pricing modelQuoteBy private worker and tier, not by user
PlatformsLinux, Self-hosted, Web, Hardware applianceWeb, Self-hosted
CategoryDatabasesDeveloper Tools

Identical on both: starting price (Free), free tier (Yes).

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 Solace PubSub+

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

Only in Spacelift

  • Multi-tool orchestration
  • Policy as code
  • Private workers
  • Spaces
  • Blueprints
  • Drift detection

What people use each for

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

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 Spacelift
  • An exchange or trading platform with a latency budget that needs the hardware appliance rather than a software brokernot Spacelift
  • An airline distributing operational events to ground systems, aircraft and partner APIs over different protocolsnot Spacelift
  • A manufacturer bridging factory MQTT telemetry into an enterprise Kafka estate without writing translation servicesnot Spacelift

Spacelift

  • Platform teams running infrastructure changes through approval gates rather than through application CInot Solace PubSub+
  • Organisations standardising Terraform and OpenTofu across many teams with policy enforcementnot Solace PubSub+
  • Estates needing private runners so cloud credentials never leave the networknot Solace PubSub+
  • Teams wanting drift detection and reconciliation rather than plan-time checks alonenot Solace PubSub+

Where each one falls short

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

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

Spacelift

  • Users are unlimited and private workers are metered, so deployment concurrency rather than headcount drives the bill, which inverts how most engineering budgets are built and is easy to under-forecast
  • There is no affordable paid entry point. The free tier stops at two users and the next tier is a five-figure commitment with nothing in between
  • Three of the five tiers are quote-only, so a shortlist cannot be costed without entering a sales process with each vendor on it
  • The self-hosted build lags the hosted one, has no public worker pool and lacks the Azure and Google Cloud integrations available in the SaaS product, with OIDC federation offered as the workaround
  • Stacks, Rego policies, Blueprints, Spaces and Spacelift-managed state are proprietary constructs, so leaving means rebuilding the orchestration layer rather than pointing it at a different runner

Pricing, plan by plan

Solace PubSub+

Free
  • Software Event Broker StandardFree
    • Free for production within capacity limits
    • Single node, capped connections and queues
    • No vendor support
  • Solace CloudOn request
    • 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-managedOn request
    • Deploy in your own Kubernetes, VMs or data centre
    • High availability and disaster recovery
    • Support with SLA
  • Hardware applianceOn request
    • Purpose-built appliance with FPGA message offload
    • Deterministic low latency
    • Sold with support contract

Spacelift

Free
  • FreeFree
    • Two users
    • Public workers only
    • No private workers
  • Starter PlusOn request
    • Unlimited users
    • Two public workers
    • One to two private workers
  • BusinessOn request
    • Unlimited users
    • Three private workers
    • Quoted
  • EnterpriseOn request
    • Unlimited users
    • Five to thirty private workers
    • Self-hosted option

Which should you pick?

Choose Solace PubSub+ if

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

Choose Spacelift if

  • You need multi-tool orchestration.
  • You want to start without paying.
  • You work on Web, Self-hosted.
  • You also want policy as code.
Spacelift review

Questions people ask

Is Solace PubSub+ or Spacelift better?
Neither clearly leads. Solace PubSub+ starts at Free and Spacelift at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Solace PubSub+ or Spacelift?
Solace PubSub+ starts at Free and Spacelift at Free.
Does Solace PubSub+ or Spacelift run on more platforms?
Solace PubSub+ runs on Linux, Self-hosted, Web, Hardware appliance. Spacelift runs on Web, Self-hosted.
Can I use Solace PubSub+ for free?
Both have a free tier, so you can try either at no cost before committing.
What is Solace PubSub+ best used for?
Solace PubSub+ is most often used for a bank building an event mesh across regions where a java jms application and an mqtt mobile client must share the same topic space, an exchange or trading platform with a latency budget that needs the hardware appliance rather than a software broker, an airline distributing operational events to ground systems, aircraft and partner apis over different protocols, a manufacturer bridging factory mqtt telemetry into an enterprise kafka estate without writing translation services. Of those, a bank building an event mesh across regions where a java jms application and an mqtt mobile client must share the same topic space and an exchange or trading platform with a latency budget that needs the hardware appliance rather than a software broker are not what Spacelift is typically brought in for.
What can Solace PubSub+ do that Spacelift cannot?
Solace PubSub+ covers Multi-protocol broker, Dynamic message routing, Hardware appliance, Event Portal. Spacelift covers Multi-tool orchestration, Policy as code, Private workers, Spaces.

Answered from the vendors’ own pages

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.

Spacelift: How is Spacelift priced?

By tier and by private worker count rather than per user. Users are unlimited on every paid plan. The published figure on the pricing page carries no period label, and the FAQ describes the tier as an annual subscription, so confirm the period in writing.

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.

Spacelift: Does it support OpenTofu?

Yes, and Spacelift sponsors the OpenTofu project, which is a substantive hedge for anyone avoiding Terraform under the Business Source Licence.

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.

Spacelift: Is there a self-hosted version?

Yes, described as carrying Enterprise functionality, but it is priced on request and lags the hosted product on cloud integrations.

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.

Spacelift: Why not just use the CI system we already have?

That is the real comparison. General purpose CI handles state, drift, approval gates and concurrency control for infrastructure poorly, and whether that is worth a five-figure floor depends on how much infrastructure change your organisation actually ships.

Spacelift: What happens to our pipelines if we leave?

They do not port. Rego policies, Blueprints, Spaces and managed state are Spacelift constructs and the orchestration has to be rebuilt elsewhere.

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