Langfuse vs Opik
Which should you use? A side-by-side look at what each one does, who it suits, what it costs, how hard it is to set up, and where each falls short.
AI tool · Open source
An open-source LLM engineering platform for tracing, prompt management, evaluations and cost tracking.
AI tool · Open source
Comet's open-source platform for logging, evaluating and monitoring LLM apps, including prompt optimisation.
The short answer
Choose Langfuse if you need…
- Tracing LLM apps in production
- Self-hosted prompt management
Choose Opik if you need…
- Open-source tracing and evals
- Automated prompt optimisation
Side-by-side
| Langfuse | Opik | |
|---|---|---|
| Type | Prompting · Evaluation & observability | Prompting · Evaluation & observability |
| Price | Open source | Open source |
| Platforms | Web, Self-hosted, API | Web, Self-hosted, API |
| Works with | LangChain, OpenAI, LlamaIndex | LangChain, OpenAI |
| Hands-on tested by us | Not yet | Not yet |
| Last checked | 2026-10-29 | 2026-10-29 |
What each one is
Langfuse
An open-source LLM engineering platform for tracing, prompt management, evaluations and cost tracking. A popular, well-documented default for observability. Self-hosting at scale needs some operational effort.
Opik
Comet's open-source platform for logging, evaluating and monitoring LLM apps, including prompt optimisation. Generous open-source feature set. Younger than some rivals, so expect rough edges.
Best for
Langfuse
- Tracing LLM apps in production
- Self-hosted prompt management
Opik
- Open-source tracing and evals
- Automated prompt optimisation
Strengths
Langfuse
- Traces and spans for LLM calls
- Prompt management with versions
- Evals and datasets
- Cost and latency dashboards
Opik
- Tracing and logging
- LLM-as-judge metrics
- Prompt library
- Agent optimiser
Frequently asked questions
What is the difference between Langfuse and Opik?
Langfuse: An open-source LLM engineering platform for tracing, prompt management, evaluations and cost tracking. Opik: Comet's open-source platform for logging, evaluating and monitoring LLM apps, including prompt optimisation. Langfuse suits tracing llm apps in production, while Opik suits open-source tracing and evals.
Are Langfuse and Opik free?
Langfuse: Open source. Opik: Open source.
What are other alternatives to Langfuse and Opik?
Other options people compare them with include Arize Phoenix, Confident AI (DeepEval), LangSmith, promptfoo, Braintrust.
Keep comparing
Built from our catalogue entries for both products: open-source details come from each project's README (AI-assisted, refreshed weekly) and GitHub data; AI-tool details are editorial. Spotted something wrong? Let us know from either product's page.