LangChain's tracing, monitoring and evaluation platform for agents.
WebsiteProvisional comparison
LangSmith vs Arize Phoenix
LangSmith is provisional S-tier and Arize Phoenix is provisional A-tier on Agent Observability & Evals. Rankings are never for sale.
Full Agent Observability & Evals tier list
Open-source tracing and evaluation for LLM apps and agents.
Website| Field | LangSmith | Arize Phoenix |
|---|---|---|
| Tier | S · provisional | A · provisional |
| Why | Most established agent tracing/eval platform; framework-agnostic. | Strong OpenTelemetry-based open-source option. |
| Pricing | freemium · starts at $39/seat/mo (Plus) | open-source / paid cloud · starts at $50/mo |
| GitHub stars | — | 11,858 |
| Last push | — | Oct 15, 2026 |
| Last verified | Oct 15, 2026 | Oct 15, 2026 |