Langfuse vs LangSmith
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 · Freemium
LangChain's platform for tracing, evaluating and monitoring LLM apps, with a prompt hub and playground.
The short answer
Choose Langfuse if you need…
- Tracing LLM apps in production
- Self-hosted prompt management
Choose LangSmith if you need…
- LangChain and LangGraph users
- Dataset-based evaluation
Side-by-side
| Langfuse | LangSmith | |
|---|---|---|
| Type | Prompting · Evaluation & observability | Prompting · Evaluation & observability |
| Price | Open source | Freemium |
| Platforms | Web, Self-hosted, API | Web, 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.
LangSmith
LangChain's platform for tracing, evaluating and monitoring LLM apps, with a prompt hub and playground. Deep tooling, especially inside the LangChain ecosystem. Less compelling if you don't use LangChain.
Best for
Langfuse
- Tracing LLM apps in production
- Self-hosted prompt management
LangSmith
- LangChain and LangGraph users
- Dataset-based evaluation
Strengths
Langfuse
- Traces and spans for LLM calls
- Prompt management with versions
- Evals and datasets
- Cost and latency dashboards
LangSmith
- Detailed run traces
- Datasets and evaluators
- Prompt hub and playground
- Production monitoring
Frequently asked questions
What is the difference between Langfuse and LangSmith?
Langfuse: An open-source LLM engineering platform for tracing, prompt management, evaluations and cost tracking. LangSmith: LangChain's platform for tracing, evaluating and monitoring LLM apps, with a prompt hub and playground. Langfuse suits tracing llm apps in production, while LangSmith suits langchain and langgraph users.
Are Langfuse and LangSmith free?
Langfuse: Open source. LangSmith: Freemium.
What are other alternatives to Langfuse and LangSmith?
Other options people compare them with include Arize Phoenix, Confident AI (DeepEval), Opik, 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.