Provider pricing

LangSmith AI API pricing

LangSmith is LangChain's observability and evaluation platform for LLM applications. It captures every prompt, tool call, and chain step, then layers automated evals, datasets, and prompt versioning on top — billed per trace with generous free and developer tiers.

Founded2023
HeadquartersSan Francisco, CA
Tracked modelsDirectory

Best for

Teams shipping LangChain or agent apps that need production observability and eval.

Strengths

  • End-to-end tracing for LangChain, LangGraph, and custom stacks
  • Built-in regression evals and human review queues
  • Prompt hub with versioning and A/B testing
  • Free tier up to 5K traces/month