CheckOps
LangSmith
LangSmith is LangChain's platform for observability and evaluation of LLM applications and agents, including offline and online evals.
Latest public signals
Last updated: 10 November 2026 (overview reviewed against langchain.com/langsmith, langchain.com/langsmith/evaluation and langchain.com/pricing).
Introduction
LangSmith is LangChain’s platform for observing and evaluating LLM applications and agents. The official evaluation page describes offline evals on curated datasets and online evals on production traffic, with human review, code or heuristic checks, LLM-as-judge evaluators and pairwise comparisons. The observability product traces agent runs and supports Python, TypeScript, Go and Java SDKs.
LangSmith is a hosted platform (self-hosted and hybrid options are listed on enterprise plans). It is separate from the open-source LangChain and LangGraph libraries.
Pricing
LangChain publishes a Developer plan that starts at $0 per seat and then pay-as-you-go, plus paid team and enterprise plans. See langchain.com/pricing for current prices and included usage.
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