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Lunary
Open-source LLM observability and prompt management for chatbots and RAG
Free plan Free trial Claimed API Self-hosted Teams
About Lunary
Lunary is a lightweight, Apache 2.0 open-source LLM observability platform for chatbots and RAG, offering tracing, prompt management, and evaluation, self-hostable or via a free-tier cloud.
Lunary is an open-source observability and analytics platform for LLM applications, with a focus on chatbots and retrieval-augmented generation. It provides request tracing, prompt management and versioning, evaluations, and user analytics, giving teams visibility into how their AI features behave in production. Because it is model-independent, it works across providers and integrates cleanly with frameworks like LangChain and OpenAI's agent tooling. Released under the Apache 2.0 license, Lunary can be self-hosted for full data control with no per-event costs, which appeals to teams with privacy or budget constraints. For those who prefer managed hosting, Lunary Cloud offers a free tier for low volumes and paid plans as usage grows. Its lightweight design makes it a fast path from zero to basic observability, positioning it as a practical open-source alternative to heavier LLMOps suites for smaller teams and side projects.
TL;DR
Lunary is a lightweight open-source LLM observability platform for chatbots and RAG, offering tracing, prompt management, and evals, self-hostable or via a free-tier cloud.
Company overview
Lunary develops an open-source observability and analytics platform for LLM applications, emphasizing simplicity and data control. It targets teams building chatbots and RAG systems who want visibility without heavyweight tooling.
The project's Apache 2.0 license and self-hosting option distinguish it from closed LLMOps suites, while Lunary Cloud provides a managed path with a free tier.
Product features
Lunary offers request tracing, prompt management and versioning, evaluations, and user analytics, all model-agnostic and integrated with LangChain and OpenAI tooling.
Teams can self-host with no per-event cost or use the cloud, making it a quick way to add observability to chatbot and RAG applications.
Target market
Startups, indie developers, and privacy-conscious teams building chatbots and RAG applications who want lightweight, open-source observability.
Buyer personas
End users
Developers building chatbots and RAG apps.
Buyers
Startup engineering leads and founders.
Key influencers
Open-source LLMOps practitioners.
Ideal customer profile
Small to mid-size teams wanting open-source, self-hostable LLM observability for chat and RAG.
Funding & performance
Independent open-source project with a commercial cloud; funding details should be verified with the vendor.
Pros & cons
Pros
- Open source under Apache 2.0
- Self-hostable with no per-event cost
- Lightweight and fast to set up
- Model-agnostic with LangChain and OpenAI support
- Free cloud tier for low volumes
- Combines tracing, prompts, and evals
Cons
- Free cloud tier capped at limited daily events
- Lighter feature set than enterprise LLMOps suites
- Smaller team and community than larger platforms
- Advanced analytics may require paid plans
- Self-hosting still requires operational effort
Key features
API
Team collaboration
Self-hosted
Multi-language
Integrations
LangChain, OpenAI, LiteLLM, REST API
Input types
text
Output types
text
Best For
chatbot observability, RAG monitoring, open-source LLMOps
Compare key features
View all alternatives →Feature
Lunary
Arize Phoenix
Opik
Pricing
Freemium
Freemium
Freemium
Free plan
Yes
Yes
Yes
Free trial
Yes
No
No
API
Yes
Yes
Yes
Self-hosted
Yes
Yes
Yes
Team support
Yes
Yes
Yes
Frequently asked questions
Is Lunary open source?+
Yes. Lunary is released under the Apache 2.0 license and can be self-hosted for full data control with no per-event fees.
What is Lunary best for?+
It is optimized for chatbot and RAG applications, providing tracing, prompt management, and evaluation.
Does Lunary have a free plan?+
Yes. You can self-host for free, and Lunary Cloud offers a free tier with a limited number of daily events.
Which frameworks does Lunary support?+
Lunary is model-agnostic and integrates with LangChain, OpenAI agents, and tools like LiteLLM.
How much does Lunary Cloud cost?+
Lunary Cloud starts around $30/month for paid plans above the free tier, with pricing scaling by usage; confirm current rates with the vendor.
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