What is LangFuse?

Concepts
Note

📚 Explanation - This page provides context and background to help you understand LangFuse and why it matters for AI observability.

LangFuse is an open-source observability platform specifically designed for Large Language Model (LLM) applications. It provides comprehensive tracing, monitoring, and analytics capabilities that help developers understand and optimize their AI-powered systems.

Core Capabilities

🔍 Tracing & Observability

  • Detailed Execution Traces - See exactly how your AI workflows execute
  • Nested Span Tracking - Monitor complex, multi-step processes
  • Real-time Monitoring - Live visibility into application performance
  • Error Tracking - Identify and diagnose issues quickly

📊 Analytics & Insights

  • Performance Metrics - Latency, throughput, and success rates
  • Cost Tracking - Monitor token usage and API costs
  • Usage Patterns - Understand how your applications are being used
  • Quality Metrics - Track model performance and output quality

🛠️ Developer Experience

  • Easy Integration - Simple Python SDK with decorator-based tracing
  • Flexible Deployment - Cloud-hosted or self-hosted options
  • Rich Dashboard - Intuitive web interface for exploring traces
  • Open Source - Full transparency and community-driven development

Why LangFuse at Justice AI?

Regulatory Compliance

  • Audit Trails - Complete records of AI decision-making processes
  • Data Sovereignty - Self-hosted deployment keeps data within MoJ infrastructure
  • Transparency - Clear visibility into how AI systems operate

Operational Excellence

  • Proactive Monitoring - Catch issues before they impact users
  • Performance Optimization - Identify bottlenecks and optimization opportunities
  • Cost Management - Track and optimize AI-related expenses

Quality Assurance

  • Model Behavior Analysis - Understand how models perform across different scenarios
  • Prompt Engineering - Iterate and improve prompts based on real usage data
  • A/B Testing - Compare different approaches and configurations

Common Use Cases

Application Development

  • RAG Systems - Monitor retrieval accuracy and generation quality
  • Chatbots - Track conversation flows and response quality
  • Document Processing - Trace multi-stage document analysis workflows
  • Decision Support - Monitor AI-assisted decision-making processes

DevOps & MLOps

  • CI/CD Integration - Automated testing and validation of AI components
  • Model Deployment - Monitor model performance in production
  • Incident Response - Quick diagnosis and resolution of AI-related issues
  • Capacity Planning - Understand resource requirements and scaling needs

Getting Started

Ready to add observability to your AI applications?

  1. Quick Start Guide - Learn by doing (Tutorial)
  2. Basic Python Tracing - Step-by-step learning (Tutorial)

Where to Go Next

Based on your experience level and goals:

New to LangFuse? 1. Quick Start - Get tracing working in 5 minutes (Tutorial) 2. Basic Python Patterns - Learn by building (Tutorial)

Ready to Implement? 1. Python SDK Guide - Full SDK capabilities (How-to guide) 2. OpenTelemetry Guide - Standardized tracing (How-to guide) 3. Raw Requests Guide - Troubleshooting with HTTP (How-to guide)

Deploy Your Own Instance? 1. Azure Deployment - Deploy LangFuse on Azure (How-to guide) 2. SSL Certificates - Configure trusted certificates (How-to guide) 3. Email Notifications - Enable user invitations (How-to guide)

Need Help? - Deployment Troubleshooting - Common issues and solutions

Architecture Overview

graph LR
    subgraph DE ["Application Environment"]
        A[Your App] --> B[LangFuse SDK]
    end
    
    subgraph SH ["Self-Hosted in AKS"]
        C[LangFuse Server]
        D[Database]
        E[Web UI]
        C --> D
        C --> E
    end
    
    B --> C

LangFuse operates as a separate service that receives trace data from your applications, providing a centralized platform for monitoring and analysis while keeping your core application logic unchanged.