langfuse-security-basics

name	langfuse-security-basics
description	Implement Langfuse security best practices for API keys and data privacy. Use when securing Langfuse integration, protecting API keys, or implementing data privacy controls for LLM observability. Trigger with phrases like "langfuse security", "langfuse API key security", "langfuse data privacy", "secure langfuse", "langfuse PII".
allowed-tools	Read, Write, Edit
version	1.12.0
license	MIT
author	Jeremy Longshore <[e-mail]>
tags	["saas","langfuse","api","security","observability"]
compatibility	Designed for Claude Code

Langfuse Security Basics

Overview

Security practices for Langfuse LLM observability: credential management, PII scrubbing before tracing, self-hosted hardening, data retention, and secret scanning.

Prerequisites

• Langfuse instance (cloud or self-hosted)
• API keys provisioned
• Understanding of data privacy requirements (GDPR, SOC2, HIPAA)

Instructions

Step 1: Credential Security

Langfuse uses two keys with different security profiles:

// Startup validation -- catch misconfigurations early
function validateLangfuseCredentials() {
  const publicKey = process.env.LANGFUSE_PUBLIC_KEY;
  const secretKey = process.env.LANGFUSE_SECRET_KEY;

  if (!publicKey || !secretKey) {
    throw new Error("LANGFUSE_PUBLIC_KEY and LANGFUSE_SECRET_KEY are required");
  }

  // Catch key swap (common mistake)
  if (secretKey.startsWith("pk-lf-")) {
    throw new Error("LANGFUSE_SECRET_KEY contains a public key (pk-lf-). Keys are swapped.");
  }

  if (publicKey.startsWith("sk-lf-")) {
    throw new Error("LANGFUSE_PUBLIC_KEY contains a secret key (sk-lf-). Keys are swapped.");
  }

  return { publicKey, secretKey };
}

// Use validated credentials
const { publicKey, secretKey } = validateLangfuseCredentials();

Key security rules: