LangSmith
LangSmith is LangChain’s observability and evaluation platform for AI agents, with tracing, monitoring, online evals and deployment for any agent framework.
About this tool
LangSmith is the platform from LangChain for understanding and improving AI agents in development and production. It records traces of every step an agent takes, including model calls, tool calls and intermediate results, so developers can see where latency, cost or answer quality break down. It works natively with popular agent frameworks and OpenTelemetry, not only with LangChain.
Monitoring dashboards show live performance, and online evaluations score quality on the criteria a team cares about. LangSmith can cluster traces automatically to surface usage patterns and failure modes, and a purpose-built trace store keeps searching deep, heavy traces fast. Beyond observability, paid plans include managed deployment for agents, with self-hosted and hybrid options for enterprises.
What you can do
Agent tracing
Follow each step of an agent run to locate errors and slow or costly calls.
Online evaluations
Score production responses automatically against the quality criteria you define.
Trace clustering
Group traces automatically to discover common behaviours, usage patterns and failure modes.
Multi-language SDKs
Instrument agents from Python, TypeScript, Go or Java, or via OpenTelemetry.
Who is it for?
- A team debugs why its support agent picks the wrong tool on certain requests.
- A product manager tracks answer quality after a prompt change with online evals.
- An enterprise self-hosts LangSmith to keep trace data in its own environment.
Before you choose
Trace volume drives cost on paid plans, so sample or filter traces for high-traffic applications.
Traces can contain user data; configure masking and retention before logging production traffic.
Frequently asked questions
Do I need LangChain to use LangSmith?
No. LangSmith traces popular agent frameworks natively and integrates with any stack through its SDKs or OpenTelemetry.
Is LangSmith free?
The Developer plan is free with one seat and 5,000 base traces per month. Plus and Enterprise plans add seats, volume and deployment options.
Can LangSmith be self-hosted?
Yes. Self-hosted and hybrid deployment options are available on the Enterprise plan for organisations that need them.
Check the official website for current features, pricing, and terms.
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