Capability · Comparison
Langfuse vs LangSmith
Langfuse and LangSmith are the two most-used tools for tracing, evaluating, and monitoring LLM applications. LangSmith is made by LangChain and integrates deeply with their stack; Langfuse is open-source, framework-agnostic, and self-hostable. The choice is mostly about your stack's shape and your ops preferences.
Side-by-side
| Criterion | Langfuse | LangSmith |
|---|---|---|
| License | MIT (open-source) | Closed, SaaS |
| Self-hosting | Yes — Docker Compose or Kubernetes | Enterprise self-host tier (paid) |
| Framework integration | LangChain, LlamaIndex, OpenAI SDK, raw HTTP | LangChain / LangGraph native; others via OTEL |
| Tracing | Yes — OpenTelemetry-compatible | Yes — first-party for LangChain |
| Datasets & evals | Yes | Yes — deeper for LangChain stack |
| Prompt management | Yes, versioned | Yes, versioned |
| Pricing (cloud) | Free tier, usage-based Pro | Free tier, usage-based Plus, Enterprise |
| Data residency / compliance | Self-host = full control | EU region available; self-host in Enterprise |
| Best for | Framework-agnostic stacks, self-host needs, cost control | LangChain + LangGraph-first teams |
Verdict
If your entire stack is LangChain and LangGraph, LangSmith is the tighter fit — prompt management, dataset evals, and tracing all feel first-party. If you use multiple frameworks (raw SDKs, LlamaIndex, custom) or need self-hosting for sovereignty and cost reasons, Langfuse wins. Both are capable observability platforms; the choice is about how framework-agnostic and how self-hostable you want your monitoring stack to be.
When to choose each
Choose Langfuse if…
- You want an open-source, self-hostable observability stack.
- Your stack is framework-agnostic or multi-framework.
- Data residency (EU, India, on-prem) is a requirement.
- You want cost control at high volume.
Choose LangSmith if…
- You're already on LangChain / LangGraph and want the first-party tooling.
- You don't want to self-host anything.
- You want the deepest possible LangChain-specific features.
- Enterprise support and SLAs from the LangChain team matter.
Frequently asked questions
Can I use Langfuse with LangChain?
Yes — Langfuse has a first-class LangChain integration, and it works cleanly alongside LangGraph. You can switch from LangSmith to Langfuse on a LangChain app with a few-line change.
What about OpenTelemetry?
Langfuse is OTEL-compatible, which makes it easier to plug into existing observability pipelines. LangSmith supports OTEL ingestion but its own SDK is the primary path.
Which is cheaper at scale?
Self-hosted Langfuse is essentially free (infrastructure cost only). LangSmith Plus scales with events; at very high volume Langfuse self-host is materially cheaper.