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Databases · head to head

Apache Pulsar vs GNAT Pro

Apache Pulsar logo

Apache Pulsar

Databases

Cloud-native messaging and streaming with separated storage

From
Free
Free plan
Yes
Visit Apache PulsarFull review
GNAT Pro logo

GNAT Pro

Developer Tools

Software development environments and toolchains for Ada, C/C++ and Rust

From
On request
Free plan
No
Visit GNAT ProFull review

The short version

  • Apache Pulsar is free; GNAT Pro prices on request.
  • Where Apache Pulsar falls short: more components than Kafka: brokers, BookKeeper and ZooKeeper each need operating.
  • Where GNAT Pro falls short: no pricing published on website; requires contacting AdaCore directly for quotes.
  • Prices and features on this page were last checked on 13 November 2026.

Where they differ

Only the attributes on which Apache Pulsar and GNAT Pro actually diverge.

Attributes where Apache Pulsar and GNAT Pro differ
AttributeApache PulsarGNAT Pro
Starting priceFreeOn request
Pricing modelOpen source, no licence feeQuote
Free tierYesNo
PlatformsLinux, Self-hostedWeb
CategoryDatabasesDeveloper Tools

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 Apache Pulsar

  • Separated storage
  • Queuing and streaming
  • Built-in multi-tenancy
  • Geo-replication

Only in GNAT Pro

Nothing recorded that Apache Pulsar does not also cover.

What people use each for

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

Apache Pulsar

  • Platforms needing both work queues and replayable streams without running two systemsnot GNAT Pro
  • Multi-tenant messaging where isolation between teams is a requirementnot GNAT Pro
  • Deployments where storage and traffic grow at genuinely different ratesnot GNAT Pro

GNAT Pro

  • Building certified avionics software meeting DO-178B/C standardsnot Apache Pulsar
  • Developing automotive embedded systems with ISO-26262 compliancenot Apache Pulsar
  • Integrating Ada, C/C++, and Rust components in single codebasenot Apache Pulsar
  • Managing software supply chain vulnerabilities and SBOMsnot Apache Pulsar
  • Supporting long-lived software systems spanning decadesnot Apache Pulsar

Where each one falls short

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

Apache Pulsar

  • More components than Kafka: brokers, BookKeeper and ZooKeeper each need operating
  • Correspondingly harder to run well, and the expertise is rarer than Kafka expertise
  • A much smaller ecosystem of connectors, tooling and hiring pool than Kafka
  • The architectural advantages only pay off at a scale most deployments never reach

GNAT Pro

  • No pricing published on website; requires contacting AdaCore directly for quotes
  • Vendor indicates per-user, per-year subscription model but does not disclose specific costs

Pricing, plan by plan

Apache Pulsar

Free
  • Apache PulsarFree
    • Full functionality
    • No usage limits
    • Community support

GNAT Pro

On request

No published plan breakdown. See the GNAT Pro review.

Which should you pick?

Choose Apache Pulsar if

  • You need separated storage.
  • You want to start without paying.
  • You work on Linux, Self-hosted.
  • You also want queuing and streaming.
Apache Pulsar review

Choose GNAT Pro if

Nothing in the data separates GNAT Pro from Apache Pulsar on the points above - pick on price and on how each one feels to use.

GNAT Pro review

Questions people ask

Is Apache Pulsar or GNAT Pro better?
Neither clearly leads. Apache Pulsar starts at Free and GNAT Pro at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Apache Pulsar or GNAT Pro?
Apache Pulsar has a free tier; the other does not. Paid plans start at Free for Apache Pulsar and On request for GNAT Pro.
Does Apache Pulsar or GNAT Pro run on more platforms?
Apache Pulsar runs on Linux, Self-hosted. GNAT Pro runs on Web.
Can I use Apache Pulsar for free?
Yes. Apache Pulsar has a free tier, so you can try it without paying. GNAT Pro starts at On request.
What is Apache Pulsar best used for?
Apache Pulsar is most often used for platforms needing both work queues and replayable streams without running two systems, multi-tenant messaging where isolation between teams is a requirement, deployments where storage and traffic grow at genuinely different rates. Of those, platforms needing both work queues and replayable streams without running two systems and multi-tenant messaging where isolation between teams is a requirement are not what GNAT Pro is typically brought in for.
What can Apache Pulsar do that GNAT Pro cannot?
Apache Pulsar covers Separated storage, Queuing and streaming, Built-in multi-tenancy, Geo-replication.

Answered from the vendors’ own pages

Apache Pulsar: Is Apache Pulsar free?

Yes, open source under the Apache Software Foundation.

GNAT Pro: How much does GNAT Pro cost?

GNAT Pro pricing is not published on the website. Customers must request a pricing quote by contacting AdaCore directly or speaking with a GNAT Pro expert.

Source
Apache Pulsar: Pulsar or Kafka?

Pulsar separates storage from compute and covers queuing and streaming in one system. Kafka has a far larger ecosystem and hiring pool. Most teams should have a specific reason before choosing Pulsar.

GNAT Pro: What is GNAT Pro licensing model?

GNAT Pro is sold on a per-user, per-year basis with no license locks. Customers can request pricing for their specific needs.

Source
Apache Pulsar: Why does separated storage matter?

Brokers hold no data, so adding or replacing one requires no rebalancing, and storage can grow without adding serving capacity.

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