LangSmith vs Langfuse
A detailed comparison to help you choose between LangSmith and Langfuse.
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Verdict: Langfuse wins
Langfuse scores 4.3/5, edging out LangSmith at 4.0/5. Engineering teams running LLM apps or agents in production who want framework-agnostic tracing and evaluation with either a cheap managed cloud or a free self-hosted stack.
LangSmith LLM ops and observability platform | Langfuse Open-source LLM observability and evaluation | |
|---|---|---|
| Rating | 4.0 (1 review) | 4.3 (1 review) |
| Pricing Model | freemium | freemium |
| Starting Price | Free tier available | Free tier available |
| Best For | Teams running LLM agents in production who need to trace, evaluate and improve them, and who will set a spend limit before trace volume grows. | Engineering teams running LLM apps or agents in production who want framework-agnostic tracing and evaluation with either a cheap managed cloud or a free self-hosted stack. |
| Free Tier | ||
| API Access | ||
| Team Features | ||
| Open Source | ||
| Tags | free tierapi access | free tieropen sourceapi access |
| Visit LangSmith → | Visit Langfuse → |
LangSmith
Pros
- + Trace-based billing is agent-friendly: a 40-step agent execution bills as one trace, not forty spans (langchain.com/pricing definition)
- + Improvement loop is complete — datasets, offline experiments, online evaluators, annotation queues and human feedback in one platform
- + Instrumentation is fast: environment variables and an SDK gave me a full nested trace tree with per-step latency and token cost
- + Framework reach beyond LangChain: documented integrations include OpenAI, Anthropic, CrewAI, Vercel AI SDK and Pydantic AI
- + Engine reads production traces to detect recurring issues and diagnose root causes — a genuine step past passive dashboards
Cons
- - Per-trace rates ($5.00 per 1,000 base, $7.50 extended) appear only in a tooltip, and secondary sources quote wildly different numbers
- - Retention upgrades fire by default — new online evaluators and automation rules push traces into the extended class at ~50% higher cost
- - Trace volume dominates the bill: one Plus seat at 100,000 traces/month computes to roughly $489 at published rates
- - Traces bill in arrears and self-hosting, SAML/OIDC SSO and RBAC are Enterprise-only, which complicates compliance-driven deployments
- - Tuned Evaluators are still public beta and the newer surfaces (Engine, Fleet) are young enough to change under you
Langfuse
Pros
- + MIT-licensed core with free, unrestricted self-hosting — only named enterprise features like audit logs and SCIM need a licence key
- + A 5-seat team at 100k traces runs roughly $69/month versus about $420/month for the main closed alternative (Panoply's independent estimate, consistent with my bills)
- + OpenTelemetry-native tracing across OpenAI SDK, LangChain, LlamaIndex, Pydantic AI, Vercel AI SDK, CrewAI and raw OTLP
- + Graduated usage pricing is transparent and cheap: worked examples on the pricing page match my own invoices (200k units on Core = $37/month)
- + Dataset-backed evaluation with the langfuse/experiment-action GitHub step let me gate prompt changes in CI on a real test set
Cons
- - v3 self-hosting needs Postgres, ClickHouse, Redis and S3 where v2 ran on one container — a four-service system to operate
- - Heavy agent traces render slowly in the UI (issue threads #10391 and #9933 match the multi-second loads I measured)
- - Online evaluations score a sample of traffic rather than everything, so rare failure modes can go unscored
- - UI-configured evaluators cannot be triggered programmatically for scheduled pipelines in my setup
- - Owned by ClickHouse, Inc. since January 2026 — licence unchanged so far, but the vendor-independence profile shifted
Frequently Asked Questions
Which is better, LangSmith or Langfuse?▼
Langfuse scores higher at 4.3/5 vs 4.0/5 for LangSmith, making it the better-rated option in our comparison.
What is the difference between LangSmith and Langfuse?▼
LangSmith: LangSmith is LangChain's platform for tracing, testing and monitoring LLM applications, with datasets and evaluations for measuring changes. Langfuse: Langfuse is open-source observability for LLM applications, tracing calls, running evaluations and tracking cost and latency in production.
Is LangSmith or Langfuse more affordable?▼
LangSmith starts at €0/mo, Langfuse starts at €0/mo. Check the comparison table above for current pricing.
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