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Machine Learning · head to head

Langwatch vs Comet ML

Langwatch logo

Langwatch

Machine Learning

LLM engineering platform for testing and evaluating AI agents in production

From
Free
Rated
-
Comet ML logo

Comet ML

Machine Learning

Platform for tracking, comparing, and optimizing ML experiments

From
Free
Rated
-

The short version

  • Each has a real cost: Langwatch free plan limited to 50k events per month, restricting larger deployments; Comet ML the free cloud tier caps data at 25,000 spans a month with 60 day retention
  • They diverge on capability: Langwatch covers Agent simulation testing, Comet ML covers Experiment tracking.

Where they differ

Only the attributes on which Langwatch and Comet ML actually diverge.

Attributes where Langwatch and Comet ML differ
AttributeLangwatchComet ML
Pricing modelTiered subscription with usage-based overage chargesfreemium
PlatformsWeb, Docker, KubernetesWeb, Linux, Mac, Windows
FoundedUnknown2017

Identical on both: starting price (Free), 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 Langwatch

  • Agent simulation testing
  • LLM evaluation
  • OpenTelemetry tracing
  • Langy AI Engineer
  • Governance controls
  • Multiple deployment options
  • Framework support

Only in Comet ML

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

What people use each for

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

Langwatch

  • Continuous testing of AI agents before production deploymentnot Comet ML
  • Automated test creation from product requirementsnot Comet ML
  • LLM response quality evaluation and scoringnot Comet ML
  • Production agent monitoring and cost trackingnot Comet ML
  • Governance and access control for AI systemsnot Comet ML

Comet ML

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

Where each one falls short

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

Langwatch

  • Free plan limited to 50k events per month, restricting larger deployments
  • Pricing in EUR may complicate budgeting for US-based teams
  • Usage-based overage model can create unpredictable costs
  • Self-hosted option requires DevOps expertise

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

Langwatch

Free
  • DeveloperFree
    • 50k events per month
    • 14-day data access
    • 2 users
  • Growth$29/month
    • 200k events per month included
    • 5 EUR per 100k additional events
    • 30-day data retention
  • Enterprise$undefined/custom
    • Custom event limits
    • Hybrid, self-hosted or on-premises deployment
    • Custom SSO and RBAC

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

Which should you pick?

Choose Langwatch if

  • You need agent simulation testing.
  • You want to start without paying.
  • You work on Web, Docker, Kubernetes.
  • You also want llm evaluation.

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.

Questions people ask

Is Langwatch or Comet ML better?
Neither clearly leads. Langwatch 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, Langwatch or Comet ML?
Langwatch starts at Free and Comet ML at Free.
Does Langwatch or Comet ML run on more platforms?
Langwatch runs on Web, Docker, Kubernetes. Comet ML runs on Web, Linux, Mac, Windows.
Can I use Langwatch for free?
Both have a free tier, so you can try either at no cost before committing.
What is Langwatch best used for?
Langwatch is most often used for continuous testing of ai agents before production deployment, automated test creation from product requirements, llm response quality evaluation and scoring, production agent monitoring and cost tracking. Of those, continuous testing of ai agents before production deployment and automated test creation from product requirements are not what Comet ML is typically brought in for.
What can Langwatch do that Comet ML cannot?
Langwatch covers Agent simulation testing, LLM evaluation, OpenTelemetry tracing, Langy AI Engineer. Comet ML covers Experiment tracking, Code versioning, Model registry, Hyperparameter optimization.

Answered from the vendors’ own pages

Langwatch: Is there a permanent free tier?

Yes, Langwatch's Developer plan is free forever with 50k events per month, 14-day data access, 2 users, and no credit card required. It is specifically designed for individual developers prototyping AI applications.

Source
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
Langwatch: What is Langy and how does it save time?

Langy is an AI-powered tool that automates test creation. It converts product requirements into test scenarios, runs simulations, scores results, and generates pull requests with fixes in a median of 14 minutes.

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
Langwatch: What frameworks does Langwatch support?

Langwatch works with LangGraph, LangChain, CrewAI, OpenAI Agents, AWS Bedrock, Azure OpenAI, Vertex AI, and other major LLM frameworks and platforms.

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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