LangSmith

What is LangSmith?

LangSmith is LangChain's observability and evaluation platform for LLM applications. It provides detailed tracing of every LLM call, chain execution, and agent step—showing inputs, outputs, latency, token usage, and cost. LangSmith includes annotation queues for human feedback, dataset management for evaluation, and regression testing for prompt changes. It's the most comprehensive debugging tool for LangChain-based applications.

Key Features

• ✓Trace visualization for LLM chains
• ✓Prompt versioning and management
• ✓Evaluation and testing suite
• ✓Dataset management
• ✓Tight LangChain integration

Common Use Cases

LangChain developers who need integrated tracing, evaluation, and prompt management

• •Debugging LangChain and LangGraph applications
• •Prompt iteration and A/B testing
• •LLM output evaluation and scoring
• •Team collaboration on prompt engineering
• •Regression testing for LLM apps