LangSmith
AI agent observability platform — tracing, monitoring, and evals for any agent stack.
Overview
LangSmith: AI Agent Observability Platform
LangSmith is the AI agent observability platform from LangChain, used by top teams to know what their agents are really doing. Trace your preferred framework or integrate LangSmith with any agent stack using SDKs for Python, TypeScript, Go, and Java — with OpenTelemetry support so you can plug it in without rewriting your stack.
LangSmith Observability gives complete visibility into agent behavior: step-by-step tracing, real-time monitoring with online evals, cost and latency tracking, and quality scoring across the trajectories that matter. Whether you are debugging a multi-turn chat agent or scoring 10,000 production calls per minute, LangSmith is the platform top AI teams use to ship great agents.
Key Features:
- Step-by-step agent tracing across frameworks
- Native tracing for popular agent stacks plus OpenTelemetry
- SDKs in Python, TypeScript, Go, and Java
- Message threading for multi-turn chat
- Real-time production monitoring with cost tracking
- Online LLM-as-judge and code evals
- Tool and agent trajectory monitoring
- Webhook and PagerDuty alerts
- Free tier for individuals; paid plans for teams and enterprise
- Built by the LangChain team
Ideal Use Case:
LangSmith is ideal for any team running LLM agents in production who needs to know what is going wrong (and where), how much it costs, and which prompts or models are improving quality release-over-release.
Why Use LangSmith:
- Industry-standard observability for AI agents
- Works with any framework, not just LangChain
- OpenTelemetry-native for plug-and-play integration
- Online evals with LLM-as-judge built in
- Free to start
FAQ
Do I need LangChain to use LangSmith? No. LangSmith works with any framework — and supports OpenTelemetry.
Which languages? Python, TypeScript, Go, and Java SDKs.
Does LangSmith track cost and latency? Yes — real-time cost tracking, latency monitoring, and quality scores.
Is there a free tier? Yes, free for individuals. Paid plans for teams.
tl;dr:
LangSmith is the AI agent observability platform from LangChain — tracing, monitoring, and online evals for any agent stack. Python, TypeScript, Go, and Java SDKs, plus OpenTelemetry.
Related
Looking for more options? Browse the AI Infrastructure directory or read our best AI infrastructure tools listicle. LangSmith is also tracked on Crunchbase.
Why Use LangSmith
FAQ
Editorial Review
Our take on LangSmith.
LangSmith is an AI agent observability platform that gives you tracing, monitoring, and evaluation tools for any agent stack.
What works
- Works with any agent stack, not vendor-locked
- Freemium tier lets you validate before commitment
- High community rating (4.86) reflects user satisfaction
What doesn't
- Observability adds operational complexity and instrumentation overhead
- Crowded category; positioning shifts as agent tooling evolves
LangSmith handles the visibility problem most teams hit when shipping AI agents: you build something, deploy it, and then realize you have almost no insight into what's actually happening in production. The platform captures traces of agent behavior, lets you monitor performance across different agent implementations, and provides evaluation tools to test outputs systematically. It's built for flexibility—works with any agent stack, not locked to a particular framework or vendor.
The freemium model means you can kick the tires without commitment, which matters when you're early in agent development and still figuring out what observability actually means for your use case. The community rating of 4.86 suggests users find real value in it. The main trade-off is that observability platforms can become another system to maintain; you need to instrument your agents to get signal, and if your setup is simple enough, the overhead might not be worth it. Also worth noting: the field is crowded and moving fast in 2026, so the specific features and competitive positioning here shift regularly.
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