Langfuse is an open-source LLM engineering platform designed for teams to collaboratively develop, monitor, evaluate, and debug AI applications. It provides observability, prompt management, evaluation tools, and a playground, catering to developers and ML engineers working with LLMs.

How It Works

Langfuse instruments applications via SDKs or integrations to capture traces of LLM calls and related logic. It offers automated instrumentation for popular frameworks like Langchain and OpenAI, and manual instrumentation for flexibility. The platform centralizes prompt management with versioning and caching, supports diverse evaluation methods (LLM-as-a-judge, user feedback, custom pipelines), and includes datasets for benchmarking.

Quick Start & Requirements

• Install via pip: pip install langfuse openai
• Set environment variables: LANGFUSE_SECRET_KEY, LANGFUSE_PUBLIC_KEY, LANGFUSE_HOST.
• Requires Python 3.x.
• Quickstart example uses OpenAI SDK.
• Documentation: https://docs.langfuse.com/
• Demo: https://cloud.langfuse.com/

Highlighted Details

• Comprehensive LLM observability for debugging and session inspection.
• Integrated prompt management with versioning and caching.
• Flexible evaluation framework supporting LLM-as-a-judge, user feedback, and custom pipelines.
• Extensive integrations with LLM frameworks (Langchain, LlamaIndex), SDKs (OpenAI, LiteLLM), and UI tools (Flowise, Langflow).
• Offers both a managed cloud deployment with a free tier and self-hosting options (Docker Compose, Kubernetes Helm).

Maintenance & Community

• Active development, YC W23 backed.
• Support and feature requests via GitHub Discussions.
• Contributing guidelines available in CONTRIBUTING.md.

Licensing & Compatibility

• MIT licensed, with exceptions for ee folders.
• Compatible with commercial use and closed-source linking, subject to MIT license terms.

Limitations & Caveats

• Telemetry is enabled by default for self-hosted instances, reporting basic usage statistics, but can be opted out.
• Specific cloud deployment guides for AWS, Google Cloud, and Azure are planned and subject to community upvotes.