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Machine Learning · head to head

Comet ML vs H2O.ai

Comet ML logo

Comet ML

Machine Learning

Platform for tracking, comparing, and optimizing ML experiments

From
Free
Rated
-
Full reviewWebsite
H2O.ai logo

H2O.ai

Machine Learning

AI Cloud for building and deploying AI applications

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Comet ML the free cloud tier caps data at 25,000 spans a month with 60 day retention; H2O.ai java is always required to run H2O-3 even when working from R or Python, and only a 64-bit JRE or JDK is supported
  • They diverge on capability: Comet ML covers Experiment tracking, H2O.ai covers AutoML.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Comet ML and H2O.ai actually diverge.

Attributes where Comet ML and H2O.ai differ
AttributeComet MLH2O.ai
PlatformsWeb, Linux, Mac, WindowsWeb, Cloud
Founded20172011

Identical on both: starting price (Free), pricing model (freemium), free tier (Yes), user rating (Not yet rated), category (Machine Learning).

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 Comet ML

  • Experiment tracking
  • Code versioning
  • Model registry
  • Hyperparameter optimization
  • Production monitoring
  • PyTorch
  • TensorFlow
  • Keras

Only in H2O.ai

  • AutoML
  • Distributed computing
  • Feature engineering
  • Model explainability
  • Time series forecasting
  • Spark
  • Hadoop
  • Python

Both cover

  • Web support
  • Linux support
  • Mac support
  • Windows support

What people use each for

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

Comet ML

  • LLM observability and monitoringnot H2O.ai
  • AI agent testing and debuggingnot H2O.ai
  • Experiment tracking for machine learningnot H2O.ai
  • Model registry and version managementnot H2O.ai
  • ML model training monitoringnot H2O.ai

H2O.ai

  • Distributed in-memory machine learning over large datasetsnot Comet ML
  • Training and productionising models from R or Python against a shared H2O clusternot Comet ML

Where each one falls short

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

Comet ML

  • The free cloud tier caps data at 25,000 spans a month with 60 day retention
  • Retention stays at 60 days even on the paid Pro plan, and extending it is a $29 per 100k spans add on
  • Overage on Pro is $5 per additional 100,000 spans
  • The free MLOps tier is a single user with 100 GB of storage and training hours governed by a fair usage policy
  • Pro MLOps is $19 per user per month and caps the team at 10 users

H2O.ai

  • Java is always required to run H2O-3 even when working from R or Python, and only a 64-bit JRE or JDK is supported
  • Supported Java versions stop at Java SE 17; newer versions only run by forcing an unsupported version flag and are guaranteed for experiments rather than production
  • H2O-3 only supports numpy below version 2, so a numpy 2 environment must be downgraded
  • Supported Python versions are limited to 3.7 through 3.11
  • The Flow web UI requires an internet browser and is the only graphical interface

Pricing, plan by plan

Comet ML

Free
  • Free CloudFree
    • Up to 10 team members
    • 25,000 spans per month
    • 60-day data retention
  • Pro Cloud$19/month
    • Up to 50 team members
    • 100,000 spans per month
    • 60-day data retention
  • MLOps FreeFree
    • 1 user with fair usage policy
    • Experiment tracking
    • Dataset management
  • MLOps Pro$19/user/month
    • Up to 10 users
    • 1,500 training hours included
    • 500GB storage included

H2O.ai

Free
  • H2O-3 Open SourceFree
    • Core algorithms
    • AutoML
    • Community support
  • Driverless AIFree
    • Automatic feature engineering
    • Model explainability
    • Enterprise support

Which should you pick?

Choose Comet ML if

  • You need experiment tracking.
  • You want to start without paying.
  • You work on Web, Linux, Mac, Windows.
  • You also want code versioning.
Comet ML review

Choose H2O.ai if

  • You need automl.
  • You want to start without paying.
  • You work on Web, Cloud.
  • You also want distributed computing.
H2O.ai review

Questions people ask

Is Comet ML or H2O.ai better?
Neither clearly leads. Comet ML starts at Free and H2O.ai at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Comet ML or H2O.ai?
Comet ML starts at Free and H2O.ai at Free.
Does Comet ML or H2O.ai run on more platforms?
Comet ML runs on Web, Linux, Mac, Windows. H2O.ai runs on Web, Cloud.
Can I use Comet ML for free?
Both have a free tier, so you can try either at no cost before committing.
What is Comet ML best used for?
Comet ML is most often used for llm observability and monitoring, ai agent testing and debugging, experiment tracking for machine learning, model registry and version management. Of those, llm observability and monitoring and ai agent testing and debugging are not what H2O.ai is typically brought in for.
What can Comet ML do that H2O.ai cannot?
Comet ML covers Experiment tracking, Code versioning, Model registry, Hyperparameter optimization. H2O.ai covers AutoML, Distributed computing, Feature engineering, Model explainability. Both handle Web support, Linux support, Mac support, Windows support.

Answered from the vendors’ own pages

Comet ML: Does Comet.ml offer a free plan?

Yes, Comet.ml offers free tiers for both Opik (cloud observability) and MLOps platforms. Free Cloud Opik includes up to 10 team members and 25,000 spans/month. Free MLOps tier is limited to 1 user.

Source
H2O.ai: Is H2O open source and free?

Yes. H2O-3 OSS is free and Apache-licensed, designed for self-managed and experimental workflows. H2O.ai also offers enterprise cloud solutions with additional features.

Source
Comet ML: How many team members can use the free Comet.ml tier?

Free Cloud supports up to 10 team members. The Pro Cloud plan supports up to 50 team members at $19/month.

Source
H2O.ai: How many companies use H2O's open source platform?

Over 18,000 companies across Finance, Insurance, Healthcare, Retail, Telco, Sales, and Marketing use H2O's open-source machine learning platform.

Source
Comet ML: What is a span in Comet.ml pricing?

A span represents a single tracked operation such as model requests or function calls. Free Cloud tier includes 25,000 spans per month.

Source
Comet ML: Does Comet.ml offer academic pricing?

Yes, a free Pro plan is available for academic users; verification is required via signup.

Source
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