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Databases · head to head

Apache Pulsar vs Flowable

Apache Pulsar logo

Apache Pulsar

Databases

Cloud-native messaging and streaming with separated storage

From
Free
Rated
-
Full reviewWebsite
Flowable logo

Flowable

Automation Integration

Apache 2.0 BPMN, CMMN and DMN engine from the team that originally built Activiti

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Apache Pulsar more components than Kafka: brokers, BookKeeper and ZooKeeper each need operating; Flowable the open source engine is genuinely usable but ships without the modelling studio, work application and admin console, so an open source deployment means building your own user interfaces before anyone can use it.
  • They diverge on capability: Apache Pulsar covers Separated storage, Flowable covers BPMN 2.0 engine.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Apache Pulsar and Flowable actually diverge.

Attributes where Apache Pulsar and Flowable differ
AttributeApache PulsarFlowable
Pricing modelOpen source, no licence feequote
PlatformsLinux, Docker, Kubernetes, Self-hostedLinux, Windows, Docker, Kubernetes, Cloud
CategoryDatabasesAutomation Integration

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated).

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 Flowable

  • BPMN 2.0 engine
  • CMMN case management
  • DMN decision tables
  • Spring Boot integration
  • Modelling studio
  • Task and case application
  • REST APIs
  • History and audit

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 Flowable
  • Multi-tenant messaging where isolation between teams is a requirementnot Flowable
  • Deployments where storage and traffic grow at genuinely different ratesnot Flowable

Flowable

  • An insurer automating claims handling where each case follows a different path and BPMN alone cannot express itnot Apache Pulsar
  • A bank embedding process orchestration inside an existing Spring Boot estate rather than buying a separate platformnot Apache Pulsar
  • A team leaving Activiti or jBPM that wants the same API family with active commercial maintenancenot Apache Pulsar
  • A regulated organisation needing complete process history and decision table audit trails for supervisorsnot 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

Flowable

  • The open source engine is genuinely usable but ships without the modelling studio, work application and admin console, so an open source deployment means building your own user interfaces before anyone can use it.
  • It expects Java engineering capacity; teams looking for a business-user low-code automation tool will find the modelling and deployment cycle far too technical.
  • Enterprise pricing is not published and is quoted per deployment, leaving buyers without a benchmark against Camunda or IBM alternatives.
  • The Activiti fork left three engines with related APIs and overlapping documentation in circulation, and search results routinely return advice for the wrong one.
  • Flowable AG is a small Swiss company relative to its competitors, so the partner network, training market and pool of engineers with production experience are all limited outside Europe.

Pricing, plan by plan

Apache Pulsar

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

Flowable

Free
  • Flowable Open SourceFree
    • Apache 2.0 licensed BPMN, CMMN and DMN engines
    • Embeddable Java library or standalone apps
    • No modelling studio or enterprise applications
  • Flowable Enterprise$undefined/year
    • Modelling studio, work application and admin console
    • Connectors, forms and advanced identity management
    • Support with SLA and version maintenance

Which should you pick?

Choose Apache Pulsar if

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

Choose Flowable if

  • You need bpmn 2.0 engine.
  • You want to start without paying.
  • You work on Linux, Windows, Docker, Kubernetes, Cloud.
  • You also want cmmn case management.
Flowable review

Questions people ask

Is Apache Pulsar or Flowable better?
Neither clearly leads. Apache Pulsar starts at Free and Flowable at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Apache Pulsar or Flowable?
Apache Pulsar starts at Free and Flowable at Free.
Does Apache Pulsar or Flowable run on more platforms?
Apache Pulsar runs on Linux, Docker, Kubernetes, Self-hosted. Flowable runs on Linux, Windows, Docker, Kubernetes, Cloud.
Can I use Apache Pulsar for free?
Both have a free tier, so you can try either at no cost before committing.
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 Flowable is typically brought in for.
What can Apache Pulsar do that Flowable cannot?
Apache Pulsar covers Separated storage, Queuing and streaming, Built-in multi-tenancy, Geo-replication. Flowable covers BPMN 2.0 engine, CMMN case management, DMN decision tables, Spring Boot integration.

Answered from the vendors’ own pages

Apache Pulsar: Is Apache Pulsar free?

Yes, open source under the Apache Software Foundation.

Flowable: Is Flowable open source?

Yes, the BPMN, CMMN and DMN engines are Apache 2.0. The modelling studio and enterprise applications are commercial.

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.

Flowable: How does it relate to Activiti and jBPM?

The same core developers built jBPM, then Activiti, then forked Activiti in 2016 to create Flowable.

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.

Flowable: What does Flowable Enterprise cost?

Nothing is published. It is quoted per deployment by the vendor.

Flowable: Why choose it over Camunda?

CMMN case management is a first-class engine, which matters when work is exception-driven rather than a fixed sequence.

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