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Databases · head to head

Apache Pulsar vs ClearML

Apache Pulsar logo

Apache Pulsar

Databases

Cloud-native messaging and streaming with separated storage

From
Free
Rated
-
Full reviewWebsite
ClearML logo

ClearML

Machine Learning

Open-source MLOps platform for experiment tracking and orchestration

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; ClearML broad scope means more to learn and more to run than a focused tracking tool
  • They diverge on capability: Apache Pulsar covers Separated storage, ClearML covers Experiment tracking.
  • Prices and features above were last checked on 29 August 2026.

Where they differ

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

Attributes where Apache Pulsar and ClearML differ
AttributeApache PulsarClearML
Pricing modelOpen source, no licence feeOpen-source self-hosted, with paid hosted and enterprise tiers
PlatformsLinux, Docker, Kubernetes, Self-hostedLinux, macOS, Windows, Docker, Kubernetes
CategoryDatabasesMachine Learning

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 ClearML

  • Experiment tracking
  • Remote execution
  • Data versioning
  • Pipelines

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

ClearML

  • Tracking experiments across a team so results are reproduciblenot Apache Pulsar
  • Moving training from laptops to shared GPU hardware without repackagingnot Apache Pulsar
  • Versioning datasets alongside the experiments that consumed themnot 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

ClearML

  • Broad scope means more to learn and more to run than a focused tracking tool
  • Self-hosting the server is real infrastructure — database, file storage and web server
  • Documentation quality is uneven across the newer parts of the platform
  • Smaller community than the most popular tracking tools, so fewer worked examples exist

Pricing, plan by plan

Apache Pulsar

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

ClearML

Free
  • Open sourceFree
    • Experiment tracking
    • Pipelines
    • Self-hosted server

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 ClearML if

  • You need experiment tracking.
  • You want to start without paying.
  • You work on Linux, macOS, Windows, Docker, Kubernetes.
  • You also want remote execution.
ClearML review

Questions people ask

Is Apache Pulsar or ClearML better?
Neither clearly leads. Apache Pulsar starts at Free and ClearML at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Apache Pulsar or ClearML?
Apache Pulsar starts at Free and ClearML at Free.
Does Apache Pulsar or ClearML run on more platforms?
Apache Pulsar runs on Linux, Docker, Kubernetes, Self-hosted. ClearML runs on Linux, macOS, Windows, Docker, Kubernetes.
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 ClearML is typically brought in for.
What can Apache Pulsar do that ClearML cannot?
Apache Pulsar covers Separated storage, Queuing and streaming, Built-in multi-tenancy, Geo-replication. ClearML covers Experiment tracking, Remote execution, Data versioning, Pipelines.

Answered from the vendors’ own pages

Apache Pulsar: Is Apache Pulsar free?

Yes, open source under the Apache Software Foundation.

ClearML: Is ClearML free?

The open-source version is free and self-hostable. Hosted and enterprise tiers are paid.

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.

ClearML: How much code does tracking require?

Very little — adding a couple of lines to an existing training script captures parameters, metrics and environment automatically.

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.

ClearML: Does ClearML replace MLflow?

It covers MLflow’s tracking and adds orchestration, remote execution and data versioning. Whether that breadth is an advantage or extra weight depends on whether you need the rest.

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