What is Comet used for?

Comet is an AI developer platform for experiment tracking, model registry and LLM evaluation, and the maker of the open-source Opik observability tool for agents. It is a good fit for tracking machine learning experiments, debugging and monitoring LLM agents, and controlling AI coding tool costs.

Yes. Comet has a free plan, and paid plans start at $19 per seat per month. A free trial is also available.

Is Comet open source?

No. Comet is proprietary (closed-source) software. Open-source alternatives to Comet include MLflow, Opik and labml.

Can I self-host Comet?

Yes. Although Comet is closed source, it can be self-hosted on your own servers, and the vendor also offers a hosted version.

What are some alternatives to Comet?

Comet competes with Weights & Biases, Arize AI and LangSmith. For open-source options, see Enlisted's ranked list of open-source Comet alternatives.

Comet: features, pricing and alternatives

About Comet

Comet is an AI developer platform that started with experiment tracking and a model registry for machine learning teams and has expanded to LLM and agent observability. It is also the creator of Opik, an open-source observability and evaluation tool for generative AI applications.

Opik covers logging every step an agent takes through traces, with a large set of integrations and an MCP server that lets coding agents read the data. Its Diagnostics feature groups recurring issues and recommends fixes, and an in-product agent named Ollie proposes changes to prompts, tool calls and retrieval steps. The platform also includes cost intelligence, including tracking Claude Code spend across an engineering team, and an agent optimizer.

Comet is commercial software with a hosted offering, a free trial and a demo, and a published pricing page. Opik itself can be used for free, and the tool suits developers who want one place to trace, test and monitor their agents.

Key features

Experiment tracking and model registry
Opik tracing for LLM applications
MCP server for coding agents
Diagnostics that group recurring errors
Cost intelligence for AI spend
Agent optimizer

Good fit for

→Tracking machine learning experiments
→Debugging and monitoring LLM agents
→Controlling AI coding tool costs

Tags: experiment-tracking; llm-observability; opik; model-registry; evaluation; agents; mlops; llmops

Comet: questions and answers

What is Comet used for?: Comet is an AI developer platform for experiment tracking, model registry and LLM evaluation, and the maker of the open-source Opik observability tool for agents. It is a good fit for tracking machine learning experiments, debugging and monitoring LLM agents, and controlling AI coding tool costs.
Is Comet free?: Yes. Comet has a free plan, and paid plans start at $19 per seat per month. A free trial is also available.
Is Comet open source?: No. Comet is proprietary (closed-source) software. Open-source alternatives to Comet include MLflow, Opik and labml.
Can I self-host Comet?: Yes. Although Comet is closed source, it can be self-hosted on your own servers, and the vendor also offers a hosted version.
What are some alternatives to Comet?: Comet competes with Weights & Biases, Arize AI and LangSmith. For open-source options, see Enlisted's ranked list of open-source Comet alternatives.