The deciding difference is operational: Braintrust can run on infrastructure you control, LangSmith cannot. If that constraint is real for you, it settles the choice before anything else is considered.
Tracing, datasets and evals from the LangChain team.
Eval-first platform — scorers, datasets and a playground for prompt iteration.
| LangSmith | Braintrust | |
|---|---|---|
| Licence | Proprietary | Proprietary |
| Pricing | freemium | freemium |
| Self-hostable | No | Yes |
| Languages | Python, TypeScript | Python, TypeScript |
| Install | — | — |
| Keys required | LANGSMITH_API_KEY | BRAINTRUST_API_KEY |
The deciding difference is operational: Braintrust can run on infrastructure you control, LangSmith cannot. If that constraint is real for you, it settles the choice before anything else is considered. LangSmith: Tracing, datasets and evals from the LangChain team. Braintrust: Eval-first platform — scorers, datasets and a playground for prompt iteration.
LangSmith is a hosted service only. Braintrust can run on your own infrastructure.
LangSmith is proprietary (freemium). Braintrust is proprietary (freemium).
Every page here answers to Accept: text/markdown and returns the same content at roughly a tenth the tokens. No separate site, no toggle — same URL.
curl -s -H "Accept: text/markdown" https://newagent.build/compare/langsmith-vs-braintrust