LangSmith
Closed-source tracing, evals and monitoring platform from the LangChain team, deepest integration with LangChain/LangGraph but usable via OTel from any stack.
| Category | Observability & Tracing |
| Open source | No |
| Self-hostable | Yes |
| Pricing model | freemium |
| Pricing notes | Free developer seat; Plus ~$39/seat/mo plus usage-based trace billing; self-hosting is enterprise-only |
| Framework integrations | langchain, langgraph, openai-sdk, opentelemetry |
| Funding / ownership | LangChain raised $125M Series B (2025) at ~$1.25B valuation |
Pricing/feature source: https://www.langchain.com/pricing