LangSmith
Debug, trace, and evaluate LangChain applications in production — see every LLM call with full context, run automated quality checks, and catch regressions before they reach users.
Overview
LangSmith is the observability and evaluation platform built by the LangChain team for teams building production LLM applications — it logs every LLM call with full trace context, lets you define evaluation datasets and run automated quality checks, and provides a debugging interface that shows exactly where a chain went wrong. Where Langfuse is framework-agnostic, LangSmith has the tightest integration with LangChain and LangGraph, making it the default choice for teams already in the LangChain ecosystem. The dataset and evaluation workflow is particularly strong for teams that run regular regression testing on their chains.
Key Features
- Full LLM call tracing
- LangChain native integration
- Evaluation datasets
- Automated regression testing
- Prompt playground
- Team collaboration
- • Native LangChain integration provides trace depth that third-party tools can't match
- • Evaluation dataset workflow is among the most mature in the LLM observability category
- • Playground lets you test chains interactively before deploying changes
- • Less useful for non-LangChain stacks compared to framework-agnostic alternatives
- • Free tier trace limits hit quickly in production