Braintrust vs LangSmith
Side-by-side comparison from the Agent Observability Index: licensing, self-hosting, pricing model and integrations — no vendor copy, primary sources linked.
| Braintrust | LangSmith | |
|---|---|---|
| One-liner | Eval-first AI engineering platform with logging, datasets, an LLM proxy and a purpose-built trace database (Brainstore), aimed at production regression-catching. | Closed-source tracing, evals and monitoring platform from the LangChain team, deepest integration with LangChain/LangGraph but usable via OTel from any stack. |
| Category | Evals & Testing | Observability & Tracing |
| Open source | No | No |
| Self-hostable | Yes | Yes |
| Pricing model | freemium | freemium |
| Pricing notes | Free developer tier; usage-based paid plans; enterprise hybrid/self-hosted data plane | Free developer seat; Plus ~$39/seat/mo plus usage-based trace billing; self-hosting is enterprise-only |
| Frameworks | openai-sdk, anthropic, langchain, vercel-ai | langchain, langgraph, openai-sdk, opentelemetry |
| Funding / ownership | $36M Series A (a16z, 2024) + $80M Series B (ICONIQ, Feb 2026, ~$800M valuation) | LangChain raised $125M Series B (2025) at ~$1.25B valuation |
How to choose
- Both link to primary pricing sources below — verify current tiers before committing; this market shifts monthly.
Sources: Braintrust · LangSmith