Is LangSmith free? What it actually costs in 2026
Yes, there is a free tier — with limits.
There is a free developer tier with a monthly trace allowance. Paid plans are seat-based with usage pricing on traces beyond the included volume, and enterprise plans (including self-hosted deployment) are quote-only. The cost that surprises people is trace volume rather than seats: a chatty agent generates many spans per user action, so the bill tracks how verbose your application is. Verified against LangChain's published pricing on 2026-07-30 — confirm current figures, as this pricing has changed repeatedly.
When paying is still the right call
If you are already building on LangChain, LangSmith is the path of least resistance and the integration genuinely is tighter than anything else. It is also the right call for teams with no appetite to run a database and a collector for their observability stack, and for anyone who needs an evaluation workflow working this week rather than assembled over a sprint.
What you are locked into
Moderate and mostly in the accumulated history. Instrumentation is the movable part — if you instrumented with OpenTelemetry conventions, switching backends is configuration. What does not move is your trace history, evaluation datasets and the scoring you built on top of them, and those are the things that took months to become useful.
If you would rather not pay: Langfuse
Langfuse
The self-hosted default for LLM tracing — MIT core, framework-agnostic.
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.
See all 4 LangSmith alternatives comparedCompare the free options head-to-head
Pricing is verified against the vendor's published figures and dated above. Vendors change prices — confirm current numbers with LangChain before you commit. More llm observability & evaluation decisions on Macrostack.