PostHog Integration - Helicone OSS LLM Observability

Introduction#

PostHog is a comprehensive product analytics platform that helps you understand user behavior and product performance.

How to Integrate#

Create an account and generate an API key

Create a Posthog account if you don't have one. Get your Project API Key from your PostHog project settings.

HELICONE_API_KEY=sk-helicone-...POSTHOG_PROJECT_API_KEY=phc_...# Optional: PostHog host (defaults to https://app.posthog.com)# Only needed if using self-hosted PostHog# POSTHOG_CLIENT_API_HOST=https://app.posthog.com

Install OpenAI

npm install openai# oryarn add openai

Configure OpenAI client with Helicone AI Gateway

import { OpenAI } from "openai";import dotenv from "dotenv";dotenv.config();const client = new OpenAI({  baseURL: "https://ai-gateway.helicone.ai",  apiKey: process.env.HELICONE_API_KEY,  defaultHeaders: {    "Helicone-Posthog-Key": POSTHOG_PROJECT_API_KEY,    "Helicone-Posthog-Host": POSTHOG_CLIENT_API_HOST  },});

You can find all 100+ supported models at helicone.ai/models.

Use the OpenAI SDK

Your existing OpenAI code continues to work without any changes. Events will automatically be exported to PostHog.

  const response = await client.chat.completions.create({    model: "gpt-4o-mini",    messages: [{ role: "user", content: "Hello, world!" }],    temperature: 0.7,  });  console.log(response.choices[0]?.message?.content);

Verify your requests in Helicone

With the above setup, any calls to Posthog will automatically be logged and monitored by Helicone. Review them in your Helicone dashboard.

Go to your PostHog Events page
Look for events with the helicone_request event name
Each event contains metadata about the LLM request including:
- Model used
- Token counts
- Latency
- Cost
- Request/response data