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Software · head to head

Neptune.ai vs Comet ML

Neptune.ai logo

Neptune.ai

Software

Metadata store for MLOps

From
Free
Rated
-
Full reviewWebsite
Comet ML logo

Comet ML

Software

Platform for tracking, comparing, and optimizing ML experiments

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Neptune.ai free tier limited to 100 hours per month, exhausted quickly with serious ML work; Comet ML the free cloud tier caps data at 25,000 spans a month with 60 day retention
  • They diverge on capability: Neptune.ai covers Metadata logging, Comet ML covers Code versioning.

Where they differ

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

Attributes where Neptune.ai and Comet ML differ
AttributeNeptune.aiComet ML
Pricing modelUnknownfreemium
PlatformsWeb, Self-hostedWeb, Linux, Mac, Windows

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Unknown), founded (2017).

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 Neptune.ai

  • Metadata logging
  • Comparison views
  • Custom dashboards
  • XGBoost

Only in Comet ML

  • Code versioning
  • Hyperparameter optimization
  • Production monitoring
  • Hugging Face

Both cover

  • Experiment tracking
  • Model registry
  • PyTorch
  • TensorFlow
  • Keras
  • scikit-learn
  • Web support
  • Linux support
  • Mac support
  • Windows support

What people use each for

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

Neptune.ai

  • Machine learningnot Comet ML
  • Data analysisnot Comet ML
  • Model trainingnot Comet ML
  • Predictive analyticsnot Comet ML

Comet ML

  • Tracking machine learning experiments, metrics and model versionsnot Neptune.ai
  • Monitoring and evaluating LLM applications with tracingnot Neptune.ai

Where each one falls short

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

Neptune.ai

  • Free tier limited to 100 hours per month, exhausted quickly with serious ML work
  • Lacks hyperparameter sweeps compared to Weights and Biases
  • No pipeline orchestration or broader MLOps lifecycle management
  • Dashboard visualization limitations - automatic resizing affects visualization order and size
  • Cloud-based SaaS only (as of last available service) requires internet connectivity

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

Pricing, plan by plan

Neptune.ai

Free

No published plan breakdown. See the Neptune.ai review.

Comet ML

Free
  • FreeFree
    • 100 experiments
    • Basic features
    • Community support
  • Team$179/month
    • Unlimited experiments
    • Team collaboration
    • Priority support

Which should you pick?

Choose Neptune.ai if

  • You need metadata logging.
  • You want to start without paying.
  • You work on Web, Self-hosted.
  • You also want comparison views.
Neptune.ai review

Choose Comet ML if

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

Questions people ask

Is Neptune.ai or Comet ML better?
Neither clearly leads. Neptune.ai starts at Free and Comet ML at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Neptune.ai or Comet ML?
Neptune.ai starts at Free and Comet ML at Free.
Does Neptune.ai or Comet ML run on more platforms?
Neptune.ai runs on Web, Self-hosted. Comet ML runs on Web, Linux, Mac, Windows.
Can I use Neptune.ai for free?
Both have a free tier, so you can try either at no cost before committing.
What is Neptune.ai best used for?
Neptune.ai is most often used for machine learning, data analysis, model training, predictive analytics. Of those, machine learning and data analysis are not what Comet ML is typically brought in for.
What can Neptune.ai do that Comet ML cannot?
Neptune.ai covers Metadata logging, Comparison views, Custom dashboards, XGBoost. Comet ML covers Code versioning, Hyperparameter optimization, Production monitoring, Hugging Face. Both handle Experiment tracking, Model registry, PyTorch, TensorFlow.

Answered from the vendors’ own pages

Neptune.ai: Does Neptune.ai support self-hosting?

Yes. Neptune can be self-hosted on a Kubernetes cluster with ClickHouse, MySQL, and Redis dependencies, allowing organizations to maintain full data control.

Source
Neptune.ai: What machine learning frameworks does Neptune integrate with?

Neptune integrates with PyTorch, TensorFlow, Keras, scikit-learn, XGBoost, LightGBM, Hugging Face Transformers, and Optuna for hyperparameter optimization.

Source
Neptune.ai: What is the cost for a team of 10 data scientists?

Neptune's Team plan costs $49 per user per month, resulting in $490/month for 10 users, comparable to Weights and Biases at $50/user.

Source
Neptune.ai: When is Neptune.ai shutting down?

Neptune.ai is shutting down its external SaaS service on March 5, 2026, following its acquisition by OpenAI in December 2025. Customers must export and migrate data before that date.

Source
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