LangSmith

platform active freemium

A developer platform for debugging, testing, evaluating, and monitoring LLM applications. Built by LangChain, LangSmith provides tracing, prompt playground, dataset management, and automated evaluation. It's designed to work seamlessly with LangChain but supports any LLM application.

Implements

Concepts this tool claims to implement:

  • Benchmark primary

    Dataset creation and management for evaluation. Custom evaluators with LLM-as-judge, heuristics, and human labeling. Evaluation experiments with comparison views.

  • Prompt Template secondary

    Prompt playground for testing and iteration. Hub for sharing and versioning prompts. Pull prompts into applications at runtime.

  • Agent Orchestration secondary

    Trace visualization for complex agent workflows. Step-by-step debugging of agent decisions, tool calls, and intermediate states.

Integration Surfaces

  • Python SDK
  • JavaScript/TypeScript SDK
  • REST API
  • LangChain native integration
  • Web dashboard
  • VS Code extension

Details

Vendor
LangChain Inc.
License
Proprietary (SDK is MIT)
Runs On
cloud
Used By
human, system

Links

Notes

LangSmith has the tightest integration with LangChain/LangGraph but works with any LLM application. Cloud-only (no self-hosting). Free tier is generous for development. Strong feature set for evaluation and debugging complex agent traces.

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