# Langfuse

> Open-source LLM observability platform for debugging AI applications.

Langfuse is an open-source LLM observability and evaluation platform that helps AI engineering teams trace, monitor, evaluate, and debug their language model applications in production. It captures detailed traces of every LLM call, prompt version, and user interaction — providing the visibility needed to understand latency, cost, quality regressions, and user satisfaction across complex AI pipelines. AI product teams at startups and enterprises use Langfuse to systematically improve their LLM applications post-deployment, catching quality issues before they impact users and informing data-driven improvements to prompts and models.

## Quick facts

- Categories: Developer Tools, AI Agents
- Pricing: Freemium (free plan + paid tiers)
- Free plan: Yes
- Official site: https://langfuse.com
- Last checked: 2026-10-22

## Key features

- LLM application tracing
- Prompt version management
- Cost and latency monitoring
- Evaluation pipelines
- User feedback collection
- Open-source and self-hostable

## Use cases

- Debugging LLM application issues
- Tracking prompt performance over time
- Monitoring AI costs in production
- A/B testing prompts

## Links

- Nextool.ai page: https://nextool.ai/tools/langfuse/
- Alternatives: https://nextool.ai/alternatives/langfuse/

Source: Nextool.ai (https://nextool.ai/tools/langfuse/). Pricing and features change; confirm on the provider's site before relying on them.