Open-source alternatives to LangSmith

4 free, open-source alternatives with 186.2K total GitHub stars. The best open-source alternative to LangSmith is Langflow, with 149.1K GitHub stars.

Updated July 2026Stats synced from GitHub

Compare LangSmith alternatives

ToolStarsForksLicenseSelf-hosted
Langflow149.1K9.2KMITYes
Langfuse28.4K2.9KMITYes
Helicone5.8K592Apache-2.0Yes
Laminar3K203Apache-2.0Yes

LangSmith is LangChain's proprietary platform for tracing, evaluating, and monitoring LLM applications. It integrates tightly with the LangChain ecosystem, but tracing data is sent to a hosted service and pricing scales with trace volume.

Open-source alternatives give you the same observability without sending data to a third party, and work with any framework, not just LangChain. If you're specifically using LangChain to build agents, note that Langflow is a visual agent builder, not an observability tool — pair it with Langfuse or Helicone if you need both.

FAQ

Is there a free, open-source alternative to LangSmith?

Yes. Langfuse, Helicone, and Laminar are all open source and self-hostable at no software cost.

What's the best open-source alternative to LangSmith?

Langfuse is the closest direct match for tracing, prompt management, and cost tracking. Helicone is a good fit if you want observability added with minimal code changes via a gateway.

Do these alternatives work outside of LangChain?

Yes. Langfuse, Helicone, and Laminar are all framework-agnostic and work with any LLM provider or agent framework, not just LangChain.

What are the top open-source alternatives to LangSmith?

Browse all open-source alternatives to LangSmith above, or explore the full Analytics category for more options.

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