# LangSmith

> LangChain's platform for tracing, monitoring, evaluating and debugging LLM apps and agents in production

Source: https://dontaskagain.com/langsmith
Website: https://www.langchain.com/langsmith?utm_source=dontaskagain
Pricing: Freemium
Categories: [Observability](https://dontaskagain.com/categories/observability.md), [Evals](https://dontaskagain.com/categories/evals.md)
Listed: 2026-10-18
Updated: 2026-10-18

LangSmith is LangChain's observability, evaluation and deployment platform for AI agents. It records what an agent does step by step, including LLM calls, tool calls and multi-turn conversations, so developers can find failures and track latency, cost and quality, whatever framework the agent uses.

**Key features:**

- Trace agents natively from popular frameworks or OpenTelemetry.
- Monitor cost, tool use and agent trajectories, with webhook and PagerDuty alerts.
- Score quality with online LLM-as-judge and code evals, datasets and annotation queues.
- Cluster traces automatically with Insights to surface usage patterns and failure modes.
- Iterate on prompts in Prompt Hub and the Playground.
- Deploy long-running agents with LangSmith Deployment and expose them as MCP servers.

SDKs are available for Python, TypeScript, Go and Java. The Developer plan is free for one seat with 5,000 traces a month; Plus is $39 per seat a month with 10,000 traces, then pay as you go, and Enterprise adds self-hosted and hybrid deployment, SSO and RBAC.

## More observability agents

- [Langfuse](https://dontaskagain.com/langfuse.md): Open-source platform for tracing, evaluating and improving LLM apps and agents, with prompt management
- [Arize](https://dontaskagain.com/arize.md): Observability and evaluation platform that traces agents, runs evals at scale and helps debug and fix them
- [Helicone](https://dontaskagain.com/helicone.md): Open-source LLM gateway and observability platform for routing, debugging and analyzing AI app requests
- [AgentOps](https://dontaskagain.com/agentops.md): Observability SDK for tracing, replaying and debugging AI agent runs across 400+ LLMs and frameworks
- [Braintrust](https://dontaskagain.com/braintrust.md): Platform for tracing agents in production, running evals and turning real traffic into regression tests
- [Galileo](https://dontaskagain.com/galileo.md): Evaluation and observability platform that turns tuned evals into low-cost runtime guardrails for agents