Free, open-source alternatives to LangSmith
Tracing and evaluation for LLM apps. 3 apps you can run yourself instead of LangSmith, sorted by how well they replace it. Each one is open source, so your data stays with you.
LangfuseBest match
LLM engineering platform for model tracing, prompt management, and application evaluation. Langfuse helps teams collaboratively debug, analyze, and iterate on their LLM applications such as chatbots or AI agents.
Opik
Evaluate, test, and ship LLM applications with a suite of observability tools to calibrate language model outputs across your dev and production lifecycle.
Agenta
LLMOps platform for prompt management, LLM evaluation, and observability. Build, evaluate, and monitor production-grade LLM applications with collaborative prompt engineering.
Side by side
Why replace LangSmith?
LangSmith works, but your data lives in someone else's account, the price can change at any time, and features can disappear. An open-source app you run yourself is yours: you choose where it runs, who can see the data, and when to update.
Questions
What is the best free alternative to LangSmith?
Langfuse is the closest open-source replacement for LangSmith in our list. Opik and Agenta are worth a look too, depending on what you need.
Can I self-host an alternative to LangSmith?
Yes. All 3 apps on this page are open source and can run on your own server, usually with Docker, or on a managed host that installs them for you.