Langfuse Hello World

Overview

Create your first Langfuse trace with real SDK calls. Demonstrates the trace/span/generation hierarchy, the observe wrapper, and the OpenAI drop-in integration.

Prerequisites

• Completed langfuse-install-auth setup
• Valid API credentials in environment variables
• OpenAI API key (for the OpenAI integration example)

Instructions

Step 1: Hello World with v4+ Modular SDK

// hello-langfuse.ts
import { startActiveObservation, observe, updateActiveObservation } from "@langfuse/tracing";
import { LangfuseSpanProcessor } from "@langfuse/otel";
import { NodeSDK } from "@opentelemetry/sdk-node";