LangChain's tracing, monitoring and evaluation platform for agents.
WebsiteProvisional comparison
LangSmith vs Promptfoo
LangSmith is provisional S-tier and Promptfoo is provisional A-tier on Agent Observability & Evals. Rankings are never for sale.
Full Agent Observability & Evals tier list
| Field | LangSmith | Promptfoo |
|---|---|---|
| Tier | S · provisional | A · provisional |
| Why | Most established agent tracing/eval platform; framework-agnostic. | Go-to open-source eval and red-team CLI (26k+ stars). |
| Pricing | freemium · starts at $39/seat/mo (Plus) | open-source / enterprise |
| GitHub stars | — | 26,019 |
| Last push | — | Oct 15, 2026 |
| Last verified | Oct 15, 2026 | Oct 15, 2026 |