Langfuse vs OpenLLMetry
Both are alternatives to LangSmith. Here's how they stack up — verified facts, no spin.
Also searched as OpenLLMetry vs Langfuse — same comparison, one verdict.
Langfuse and OpenLLMetry are closely matched on ownership (90 vs 92) — this one comes down to pricing and to which trade-offs below you can live with.
Langfuse
TOP PICKThe self-hosted default for LLM tracing — MIT core, framework-agnostic.
Langfuse is the most widely adopted open LLM observability platform: tracing, evaluation, prompt management and cost tracking, deployable with Docker on your own infrastructure so traces containing customer data never leave your network. It is deliberately framework-agnostic — LangChain, LlamaIndex, the provider SDKs directly, or OpenTelemetry — which makes it the natural exit from a LangChain-shaped tool. At 32k stars with commits landing daily it is the healthiest project in this category. Licensing needs precision: the core is MIT Expat, while the ee/ directories carry a separate enterprise licence.
OpenLLMetry
Apache-2.0 OpenTelemetry instrumentation — send traces anywhere you already send them.
OpenLLMetry takes the opposite approach to a platform: it is a set of Apache-2.0 OpenTelemetry extensions that emit LLM traces in a standard format, so they flow into whatever you already run — Grafana, Datadog, Honeycomb, Jaeger or Traceloop's own hosted backend. If you already have observability infrastructure, this adds LLM visibility to it rather than asking you to adopt a second, parallel system. It is also the strongest hedge against lock-in: standard telemetry moves between backends by configuration.
Side by side
10 points of comparison, every one read from a verified field. Green marks the side that wins a row outright. A dash means we do not hold that fact — never that it is zero.
| Langfuse | OpenLLMetry | |
|---|---|---|
| Sovereignty ScoreOur transparent 0–100 composite for data ownership and exit cost. | 90 | 92 |
| Open source | Yes | Yes |
| Self-hostable | Yes | Yes |
| Local-first data | Yes | Yes |
| License | MIT Expat (core); ee/ directories under a separate enterprise licence | Apache-2.0 |
| Pricing | Free to self-host — Docker Compose or Kubernetes, costs are your own infrastructure. A managed cloud with a free tier and paid plans exists if you would rather not run it. | Free — Apache-2.0 instrumentation libraries. You pay only whatever backend you already send telemetry to; a hosted Traceloop backend is available separately. |
| RAM to run it wellThe figure that actually matters, not the vendor's minimum. | 4 GB | — |
| Realistic running costWhat the box costs each month if you run it yourself. | $24–40/mo plus Postgres and ClickHouse, against per-trace observability pricing | — |
| Setup timeHonest first-install estimate, not the marketing quickstart. | 2 hours | — |
| Ongoing maintenanceThe part nobody budgets for. | Moderate. Five components, and trace volume grows faster than teams expect. | — |
Langfuse is Macrostack's recommended LangSmith alternative, so it's our pick here.
Weighing both against staying on LangSmith? Is LangSmith free? What it actually costs →
Langfuse
Strengths
- +Self-hosted: prompts and completions stay inside your network
- +Framework-agnostic — not tied to any one orchestration library
- +Tracing, evals, prompt management and cost tracking in one tool
- +32k stars and daily commits — the most active project in this category
Trade-offs
- −Self-hosting means running Postgres, ClickHouse and the collector yourself
- −The MIT core stops at the ee/ directories; SSO and some enterprise features sit behind a separate licence
- −Evaluation tooling is less polished than LangSmith's if you live inside LangChain
- −Trace storage grows fast — retention policy is your problem to plan
OpenLLMetry
Strengths
- +Apache-2.0 throughout — no enterprise-directory carve-out
- +Standard OpenTelemetry: traces go to a backend you already operate
- +The best protection against lock-in — switching backends is configuration
- +Reuses your existing observability stack instead of adding a parallel one
Trade-offs
- −Instrumentation, not a platform — no evaluation or prompt-management UI
- −You need a trace backend already, or you are choosing one anyway
- −Generic backends render LLM traces less legibly than a purpose-built UI
- −Smaller project (about 7k stars) than Langfuse
Which one fits you
The trade-offs above, turned into a decision. Find the line that describes your team.
Choose Langfuse
if self-hosted: prompts and completions stay inside your network.
Choose OpenLLMetry
if a lower exit cost matters more to you than any single feature, and apache-2.0 throughout — no enterprise-directory carve-out.
Neither, yet
if both carry a real cost you should weigh first — self-hosting means running Postgres, ClickHouse and the collector yourself, and instrumentation, not a platform — no evaluation or prompt-management UI. If either of those is a dealbreaker for your team, the shortlist is wrong rather than the choice.
What it takes to run these yourself
Real requirements and honest running costs, not the vendor quickstart.
Langfuse vs OpenLLMetry — common questions
Is Langfuse a better fit than OpenLLMetry for llm observability & evaluation?
It depends on what you are optimising for, and the honest split is this: OpenLLMetry scores 92 to Langfuse's 90 on data ownership and exit cost, so it is the safer choice if you care about being able to leave. Langfuse earns its place on a different axis — self-hosted: prompts and completions stay inside your network. Neither is a wrong answer for every team; the table above is the actual comparison.
What happens if we want to switch later?
Langfuse keeps its data local or in open formats, so leaving is an export rather than a negotiation. OpenLLMetry is still self-hostable, so the files stay on your server either way — but it is not local-first by design, so check what its export produces before you rely on it.
Can I self-host Langfuse or OpenLLMetry?
Both can be self-hosted. The difference is what it costs you in time rather than whether it is possible — see the setup and maintenance rows above.
Are Langfuse and OpenLLMetry both alternatives to LangSmith?
Yes — both appear in our LangSmith comparison, which is why they are worth putting side by side. People usually arrive here already having decided to move off LangSmith and now choosing between the two replacements, which is a narrower and much easier question.
Related alternative guides
Facts verified 2026-07-30. Licenses and pricing change — spotted something out of date? That's a correction we want.