Langfuse

Open-source LLM observability and analytics platform

Code & DevelopmentFreemium

Langfuse is an open-source LLM engineering platform for observability, metrics, prompt management, and evaluations. Teams use it to trace LLM calls, monitor costs and latency, run evals on outputs, and iterate on prompts — all in one platform. Langfuse integrates with LangChain, LlamaIndex, OpenAI SDK, and others.

Key Features

• ✓LLM call tracing and spans
• ✓Cost and latency monitoring
• ✓Prompt versioning and management
• ✓Built-in and custom evaluations
• ✓Dataset management for fine-tuning
• ✓Self-hostable open-source