Comet Lab Atlas

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's ideally used

A fit when you want observability and versioned prompt management together, in a self-hostable tool.

Where it doesn't fit

A smaller ecosystem than the leading platforms — less of a fit when integration breadth is decisive.