Langfuse vs LangSmith

Langfuse and LangSmith both provide tracing, evaluation, and prompt management for LLM applications, but they sit in different ecosystems. Langfuse is open source (MIT for the core, with enterprise features under a separate license), framework-agnostic, and can be fully self-hosted or used as Langfuse Cloud. LangSmith is proprietary, tightly integrated with LangChain and LangGraph, and runs on LangChain's hosted infrastructure (with a self-hosted option for enterprise plans).

If the application is built on LangChain or LangGraph and the team wants the deepest integration with that ecosystem (graph debugging, agent traces wired into the framework primitives), LangSmith is the smoother fit. If the application uses multiple frameworks or none, or if self-hosting matters for compliance or data residency, Langfuse covers a wider surface area. Both offer comparable core tracing, evaluation workflows, and prompt management. The decision usually comes down to ecosystem alignment and hosting model rather than feature parity.