Lunary
An open-source observability and prompt-management platform for LLM applications.
Lunary is an open-source platform that pairs LLM observability (logging, tracing, cost and feedback tracking) with prompt management, so prompts are versioned and tested rather than scattered through code.
It self-hosts and aims to be a lightweight, practical home for both concerns.
Where it fits
A fit when you want observability and versioned prompt management together, in a self-hostable tool.
Where it does not fit
A smaller ecosystem than the leading platforms: less of a fit when integration breadth is decisive.
Alternatives to Lunary
The closest options on the map, and where each fits instead.
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Langfuse LLM observability
A strong default whenever an AI system reaches production and you need to see what it actually did, call by call.
Unlike Lunary Maturity: established
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Helicone LLM observability
A fit when you want fast, low-effort visibility into model calls, costs, and latency through a simple proxy.
Unlike Lunary Maturity: established
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LangSmith LLM observability
A natural fit when a project is built on LangChain or LangGraph and you want tracing and evals from the same ecosystem.
Unlike Lunary ProprietaryNot self-hostableMaturity: established
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Opik LLM observability
A fit when you want an open-source, self-hostable platform spanning tracing, evals, and production monitoring.
Pairs with
Commonly used alongside it.
