Pydantic Logfire is open source and LangSmith is not, so the question is whether you want source access and the option to fork, or would rather have a vendor accountable for it.
Tracing, datasets and evals from the LangChain team.
OpenTelemetry observability with first-class Python and Pydantic AI support.
| LangSmith | Pydantic Logfire | |
|---|---|---|
| Licence | Proprietary | Open source |
| Pricing | freemium | freemium |
| Self-hostable | No | No |
| Languages | Python, TypeScript | Python, TypeScript |
| Install | — | pip install logfire |
| Keys required | LANGSMITH_API_KEY | LOGFIRE_TOKEN |
Pydantic Logfire is open source and LangSmith is not, so the question is whether you want source access and the option to fork, or would rather have a vendor accountable for it. LangSmith: Tracing, datasets and evals from the LangChain team. Pydantic Logfire: OpenTelemetry observability with first-class Python and Pydantic AI support.
LangSmith is a hosted service only. Pydantic Logfire is a hosted service only.
LangSmith is proprietary (freemium). Pydantic Logfire is open source (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-logfire