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Opik

LLM evaluation and tracing by Comet

open sourceupdated Aug 16, 2026

Opik is an open-source LLM evaluation and tracing platform by Comet ML for debugging, testing, and monitoring AI applications. Provides detailed traces of LLM calls with latency, token usage, and cost tracking. Features automated evaluation with built-in and custom metrics, dataset management for regression testing, and production monitoring dashboards. Integrates with the broader Comet ML experiment tracking ecosystem. Available as both self-hosted open-source and managed cloud service.

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A detailed review by the aicoolies team — click to read

Opik provides LLM observability from the Comet ML ecosystem. Detailed tracing captures every step of LLM application execution with inputs, outputs, latency, and costs.

Automated evaluation with built-in metrics (faithfulness, relevancy, hallucination) and custom scorers. Dataset management enables systematic regression testing across application versions.

Production monitoring dashboards track quality, latency, and cost metrics over time. Integrates with Comet ML's broader experiment tracking for ML teams.

Open-source with self-hosted option. Comet Cloud provides managed deployment with additional features.

Pricing

Free open-source / Comet Cloud available

full pricing breakdown →

Platforms

Python, Self-hosted, Docker, Cloud

Categories

Tags

Use Cases

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Comparisons

Opik vs Langfuse: AI Optimization Suite or Open LLM Platform?

Opik and Langfuse are two credible open-source choices for tracing, evaluating, and improving LLM applications and agents. Opik, from Comet, combines observability, test suites, assertions, prompt experiments, production monitoring, and automatic prompt optimization. Langfuse combines agent and application tracing, prompt management, datasets, online and offline evaluation, feedback, and mature self-hosting. **Langfuse is the better default** because it has the broader adoption base, a particularly complete prompt-and-observability workflow, and flexible free or managed deployment. Opik is the better specialist when built-in optimization algorithms and the Comet ecosystem are decisive.

FAQ

What is Opik?

Opik is an open-source LLM evaluation and tracing platform by Comet ML for debugging, testing, and monitoring AI applications. Provides detailed traces of LLM calls with latency, token usage, and cost tracking. Features automated evaluation with built-in and custom metrics, dataset management for regression testing, and production monitoring dashboards. Integrates with the broader Comet ML experiment tracking ecosystem. Available as both self-hosted open-source and managed cloud service.

Is Opik free?

Yes — Opik is open source and free to use. Free open-source / Comet Cloud available

Is Opik open source?

Yes — Opik is open source.

What are the best Opik alternatives?

The top editor-verified Opik alternatives are Beszel, TensorZero.

How does Opik score in our review?

Our hands-on review scores Opik 81/100 overall, based on speed, privacy, and developer-experience testing.