LangSmith
LLM observability + evals from the LangChain team — production tracing for AI apps.
Visit LangSmith Free 5k traces/mo, Plus $39/mo
Quick verdict
- Best for
- LangChain developers
- Pricing
- Free 5k traces/mo, Plus $39/mo
- Not ideal if
- Tied to LangChain ergonomics (still works without)
What is LangSmith?
LangSmith is the production observability platform from the LangChain team. Trace every LLM call, debug failed agent runs, build eval datasets, A/B test prompts. Works with any LLM framework, not just LangChain.
Key features
- Full LLM call tracing
- Eval datasets + scoring
- Prompt playground + versioning
- A/B testing flows
- Framework-agnostic SDK
- Self-hostable enterprise option
Pros
- Industry-standard tracing for LangChain users
- Strong eval framework
- Free tier good for prototyping
Cons
- Tied to LangChain ergonomics (still works without)
- Self-hosted is enterprise-only
- Some features paywalled
Best for
LangChain developersTeams debugging agent workflowsAI engineers building eval pipelinesAnyone tracing LLM production traffic
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