Is LangSmith free? What it actually costs in 2026
LangSmith's Developer plan is free forever, but it is one seat and 5,000 traces a month — and a chatty agent spends those in days.
The Developer plan costs $0 per seat and includes 5,000 base traces a month, then bills pay-as-you-go. Community support, and a hard ceiling of one seat.
What the free tier actually includes
- 1 seat maximum — there is no second person on the free plan
- 5,000 base traces per month included, pay-as-you-go beyond
- Community support only
- No managed deployment (Plus includes one free small serverless deployment)
- 5 LCU of Fleet usage and 5 LCU / 1 LSU of Sandbox usage a month
Where the wall is
Two things, and the second one surprises people. The first is the second seat: the free plan is capped at one, so a colleague reviewing a trace means upgrading. The second is that traces are counted per span, not per conversation — one agent run with tool calls and retries can write dozens, so 5,000 is a week for a real application rather than a month.
After that: Plus at $39 per seat per month with 10,000 base traces, unlimited seats and one free small serverless deployment; usage beyond that is metered in LangChain Compute Units ($1.50 each) and Storage Units ($1.00 each). Enterprise is quote-only.
Can you self-host LangSmith? Paid plans only
Self-hosted and hybrid deployment exist only on the Enterprise plan, alongside custom SSO, ABAC and RBAC — so running LangSmith on your own infrastructure is a sales conversation, not a download.
What it actually takes to run one yourself
Real RAM against the documented minimum, monthly cost, setup time, and the one thing that catches people out.
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
Read from LangChain's own pricing and documentation on 2026-09-12 — 1 days ago. Vendors change prices without notice; confirm before you commit.