Langfuse Integration

Langfuse is an open-source LLM engineering platform for tracing, evaluation, prompt management, and monitoring. It integrates with popular frameworks and supports custom LLM providers.

Langfuse traces LLM calls through its SDK wrappers. Configure the underlying provider to use LLM API.

Prerequisites

An LLM API account with an API key
Langfuse installed or accessible

Setup

Get Your LLM API Key

Log in to your LLM API dashboard
Click Create Key to Start
Copy your new API key immediately — it will only be shown once
Store the key securely (e.g., in a password manager or .env file)

LLM API is an OpenAI-compatible gateway that gives you access to dozens of AI models through a single API key and endpoint.

Use LLM API with Langfuse

Install Langfuse:

pip install langfuse openai

Configure:

from langfuse.openai import openai
import os
os.environ["OPENAI_API_KEY"] = "your-llm-api-key-here"
os.environ["OPENAI_BASE_URL"] = "https://api.llmapi.ai/v1"
os.environ["LANGFUSE_SECRET_KEY"] = "your-langfuse-key"
os.environ["LANGFUSE_PUBLIC_KEY"] = "your-langfuse-public-key"

Langfuse will trace all LLM API calls automatically.

Test the Integration

Verify that Langfuse can successfully communicate with LLM API by sending a test request. All requests will now be routed through LLM API.

Langfuse's drop-in OpenAI wrapper captures every LLM API request for analysis.

Benefits of Using LLM API with Langfuse

Multi-Provider Access: Use models from OpenAI, Anthropic, Google, and more through a single API
Cost Control: Track and limit your AI spending with detailed usage analytics
Unified Billing: One account for all providers instead of managing multiple API keys
Caching: Reduce costs with response caching for repeated requests

View all available models on the models page.