Instrument Integration

PostHogOfficialCreated by PostHog

Skill
Tool integration
Data and AI
MIT
Low risk

From the author

Add PostHog SDK integration to your application. Use when setting up PostHog for the first time or reviewing PRs that need PostHog initialization. Covers SDK installation, provider setup, and basic configuration for any framework.

— the description by PostHog

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

This skill provides a structured, multi-step procedure for integrating the PostHog SDK into a wide range of web, mobile, and backend frameworks. It handles the detection of the project environment, installation of the appropriate SDK, initialization, user identification, and secure configuration of environment variables. The skill emphasizes following framework-specific patterns and maintaining an analytics contract, ensuring that PostHog is implemented consistently without disrupting existing application logic.

What it does

Detects the project's framework, language, and package manager.
Installs the correct PostHog SDK for the identified platform.
Configures PostHog initialization and provider setup based on framework-specific references.
Implements user identification logic for login and signup events.
Manages environment variables for project tokens and host URLs securely.
Verifies the integration and performs minimal cleanup.

When to use it

When setting up PostHog in a project for the first time.
When reviewing pull requests that require PostHog initialization.
When adding analytics to a new application across supported frameworks.
When migrating or updating PostHog configurations in an existing codebase.

Advantages

Ensures consistent implementation across diverse technology stacks.
Prevents hardcoding of sensitive project tokens and host URLs.
Follows established framework-specific best practices and patterns.
Minimizes the risk of breaking application boot or build processes.
Automates the repetitive aspects of SDK setup and environment configuration.

Usage examples

“Set up PostHog in my Next.js project.”: The agent will detect the Next.js environment, install the PostHog SDK, configure the necessary provider, and set up environment variables in .env.local.
“Integrate PostHog into this Android app.”: The agent will identify the Android/Kotlin structure, initialize PostHog in the Application class, and guide the setup of local.properties for configuration.

Install

Download the skill as a ZIP:
https://autogineer.com/agent-skills/posthog/instrument-integration/download

Unzip it into the cross-client skills folder of your project:

mkdir -p .agents/skills && unzip instrument-integration.zip -d .agents/skills

Documentation by PostHog

Add PostHog SDK integration

Use this skill to add the PostHog SDK to an application. Use it when setting up PostHog for the first time, or reviewing PRs that need PostHog initialization. Covers SDK installation, provider setup, and basic configuration. Supports any framework or language.

Supported frameworks and languages: Next.js, React, React Router, Vue, Nuxt, TanStack Start, SvelteKit, Astro, Angular, Django, Flask, FastAPI, Laravel, PHP, Ruby on Rails, Go, Elixir, Android, iOS, Swift, Flutter, React Native, Expo, Node.js, and vanilla JavaScript.

Instructions

Follow these steps IN ORDER:

STEP 1: Analyze the codebase and detect the platform.

Look for dependency files (package.json, pubspec.yaml, Podfile, Package.swift, requirements.txt, Gemfile, composer.json, go.mod, mix.exs, etc.) to determine the framework and language.

Look for lockfiles (pnpm-lock.yaml, package-lock.json, yarn.lock, bun.lockb, go.sum, pubspec.lock, Podfile.lock, Package.resolved, mix.lock) to determine the package manager.

Check for existing PostHog setup. If PostHog is already installed and initialized, do not modify its code. Inform the user and skip to verification.

STEP 2: Research integration. 2.1. Find the reference file below that matches the detected framework — it is the source of truth for SDK initialization, provider setup, and configuration patterns. Read it now. 2.2. If no reference matches, fall back to your general knowledge and web search. Use posthog.com/docs as the primary search source.

STEP 3: Install the PostHog SDK.

Add the PostHog SDK package for the detected platform. Do not manually edit package.json — use the package manager's install command.

STEP 4: Initialize PostHog.

Follow the framework reference for where and how to initialize. This varies significantly by framework (e.g., instrumentation-client.ts for Next.js 15.3+, AppConfig.ready() for Django, create_app() for Flask).
Set up the PostHog provider/wrapper component if the framework requires one.

STEP 5: Identify users.

Add PostHog identify() calls on the client side during login and signup events.
If both frontend and backend exist, pass the client-side session and distinct ID using X-POSTHOG-DISTINCT-ID and X-POSTHOG-SESSION-ID headers to the server-side code.

STEP 6: Set up environment variables.

Check if the project already has PostHog environment variables configured (e.g. in .env, .env.local, or framework-specific env files). If valid values already exist, skip this step.
If the PostHog project token is missing, use the PostHog MCP server's projects-get tool to retrieve the project's api_token. If multiple projects are returned, ask the user which project to use. If the MCP server is not connected or not authenticated, ask the user for their PostHog project token instead.
For the PostHog host URL: check the projects-get MCP response for a region field — US maps to https://us.i.posthog.com, EU maps to https://eu.i.posthog.com. If the region is not available from the MCP response or from existing project configuration, ask the user: "Are you on PostHog US Cloud or EU Cloud?" Do not assume US Cloud.
Write these values to the appropriate env file (e.g. .env.local for Next.js, .env for others) using the framework's naming convention.
Reference these environment variables in code instead of hardcoding them.

STEP 7: Verify and clean up.

Check the project for errors. Look for type checking or build scripts in package.json.
Ensure any components created were actually used.
Run any linter or prettier-like scripts found in the package.json, but ONLY on the files you have edited or created during this session. Never run formatting or linting across the entire project's codebase.

Reference files

references/EXAMPLE-next-app-router.md - next-app-router example project code
references/EXAMPLE-next-pages-router.md - next-pages-router example project code
references/EXAMPLE-react-react-router-6.md - react-react-router-6 example project code
references/EXAMPLE-react-react-router-7-framework.md - react-react-router-7-framework example project code
references/EXAMPLE-react-react-router-7-data.md - react-react-router-7-data example project code
references/EXAMPLE-react-react-router-7-declarative.md - react-react-router-7-declarative example project code
references/EXAMPLE-react-vite.md - react-vite example project code
references/EXAMPLE-nuxt-3-6.md - nuxt-3-6 example project code
references/EXAMPLE-nuxt-4.md - nuxt-4 example project code
references/EXAMPLE-vue-3.md - vue-3 example project code
references/EXAMPLE-react-tanstack-router-file-based.md - react-tanstack-router-file-based example project code
references/EXAMPLE-react-tanstack-router-code-based.md - react-tanstack-router-code-based example project code
references/EXAMPLE-tanstack-start.md - tanstack-start example project code
references/EXAMPLE-sveltekit.md - sveltekit example project code
references/EXAMPLE-astro-static.md - astro-static example project code
references/EXAMPLE-astro-view-transitions.md - astro-view-transitions example project code
references/EXAMPLE-astro-ssr.md - astro-ssr example project code
references/EXAMPLE-astro-hybrid.md - astro-hybrid example project code
references/EXAMPLE-angular.md - angular example project code
references/EXAMPLE-javascript-node.md - javascript-node example project code
references/EXAMPLE-javascript-web.md - javascript-web example project code
references/EXAMPLE-django.md - django example project code
references/EXAMPLE-flask.md - flask example project code
references/EXAMPLE-fastapi.md - fastapi example project code
references/EXAMPLE-python.md - python example project code
references/EXAMPLE-laravel.md - laravel example project code
references/EXAMPLE-php.md - php example project code
references/EXAMPLE-ruby-on-rails.md - ruby-on-rails example project code
references/EXAMPLE-ruby.md - ruby example project code
references/EXAMPLE-android.md - android example project code
references/EXAMPLE-swift.md - swift example project code
references/EXAMPLE-react-native.md - react-native example project code
references/EXAMPLE-expo.md - expo example project code
references/next-js.md - Next.js
references/react.md - React
references/react-router-v6.md - React router v6
references/react-router-v7-framework-mode.md - React router v7 framework mode (remix v3)
references/react-router-v7-data-mode.md - React router v7 data mode
references/react-router-v7-declarative-mode.md - React router v7 declarative mode
references/nuxt-js-3-6.md - Nuxt.js (v3.0 to v3.6)
references/nuxt-js.md - Nuxt.js
references/vue-js.md - Vue.js
references/tanstack-start.md - Tanstack start
references/svelte.md - Svelte
references/astro.md - Astro
references/angular.md - Angular
references/js.md - JavaScript web
references/posthog-js.md - PostHog JavaScript web SDK
references/node.md - Node.js
references/posthog-node.md - PostHog Node.js SDK
references/django.md - Django
references/flask.md - Flask
references/python.md - Python
references/posthog-python.md - PostHog python SDK
references/dotnet.md - .net
references/elixir.md - Elixir
references/go.md - Go
references/laravel.md - Laravel
references/php.md - Php
references/ruby-on-rails.md - Ruby on rails
references/ruby.md - Ruby
references/android.md - Android
references/ios.md - Ios
references/usage.md - Ios SDK usage
references/configuration.md - Ios SDK configuration
references/flutter.md - Flutter
references/react-native.md - React native
references/identify-users.md - Identify users
references/COMMANDMENTS.md - Framework-specific rules the integration must follow

Each framework reference contains SDK-specific installation, initialization, and usage patterns. Find the one matching the user's stack.

Key principles

Environment variables: Always use environment variables for PostHog keys. Never hardcode them.
Minimal changes: Add PostHog code alongside existing integrations. Don't replace or restructure existing code.
Match the example: Your implementation should follow the example project's patterns as closely as possible.
Analytics contract: Treat event names, property names, and feature flag keys as part of an analytics contract. Reuse existing names and patterns found in the project. When introducing new ones, make them clear, descriptive, and consistent with existing conventions.

Files

ATTRIBUTION.mdAdded by AutoGineer952 B
LICENSELicence file added by AutoGineer1.0 KiB
SKILL.md8.8 KiB
references/COMMANDMENTS.md1.5 KiB
references/EXAMPLE-android.md49.8 KiB
references/EXAMPLE-angular.md23.1 KiB
references/EXAMPLE-astro-hybrid.md27.5 KiB
references/EXAMPLE-astro-ssr.md27.6 KiB
references/EXAMPLE-astro-static.md19.6 KiB
references/EXAMPLE-astro-view-transitions.md23.3 KiB
references/EXAMPLE-django.md30.7 KiB
references/EXAMPLE-expo.md35.1 KiB
references/EXAMPLE-fastapi.md40.9 KiB
references/EXAMPLE-flask.md32.4 KiB
references/EXAMPLE-javascript-node.md9.0 KiB
references/EXAMPLE-javascript-web.md11.8 KiB
references/EXAMPLE-laravel.md59.3 KiB
references/EXAMPLE-next-app-router.md17.6 KiB
references/EXAMPLE-next-pages-router.md19.1 KiB
references/EXAMPLE-nuxt-3-6.md22.3 KiB
references/EXAMPLE-nuxt-4.md28.9 KiB
references/EXAMPLE-php.md13.0 KiB
references/EXAMPLE-python.md11.6 KiB
references/EXAMPLE-react-native.md46.0 KiB
references/EXAMPLE-react-react-router-6.md13.5 KiB
references/EXAMPLE-react-react-router-7-data.md20.1 KiB
references/EXAMPLE-react-react-router-7-declarative.md15.0 KiB
references/EXAMPLE-react-react-router-7-framework.md32.5 KiB
references/EXAMPLE-react-tanstack-router-code-based.md19.6 KiB
references/EXAMPLE-react-tanstack-router-file-based.md18.3 KiB
references/EXAMPLE-react-vite.md12.4 KiB
references/EXAMPLE-ruby-on-rails.md38.0 KiB
references/EXAMPLE-ruby.md10.0 KiB
references/EXAMPLE-sveltekit.md18.6 KiB
references/EXAMPLE-swift.md18.8 KiB
references/EXAMPLE-tanstack-start.md29.9 KiB
references/EXAMPLE-vue-3.md17.9 KiB
references/android.md33.3 KiB
references/angular.md16.5 KiB
references/astro.md15.8 KiB
references/configuration.md17.2 KiB
references/django.md14.9 KiB
references/dotnet.md25.8 KiB
references/elixir.md17.6 KiB
references/flask.md8.1 KiB
references/flutter.md42.8 KiB
references/go.md20.1 KiB
references/identify-users.md12.2 KiB
references/ios.md8.0 KiB
references/js.md16.1 KiB
references/laravel.md13.1 KiB
references/next-js.md18.3 KiB
references/node.md45.6 KiB
references/nuxt-js-3-6.md11.4 KiB
references/nuxt-js.md15.1 KiB
references/php.md23.7 KiB
references/posthog-js.md51.6 KiB
references/posthog-node.md33.9 KiB
references/posthog-python.md69.3 KiB
references/python.md52.2 KiB
references/react-native.md59.9 KiB
references/react-router-v6.md13.6 KiB
references/react-router-v7-data-mode.md13.5 KiB
references/react-router-v7-declarative-mode.md13.7 KiB
references/react-router-v7-framework-mode.md20.2 KiB
references/react.md21.9 KiB
references/ruby-on-rails.md19.7 KiB
references/ruby.md25.5 KiB
references/svelte.md14.6 KiB
references/tanstack-start.md12.8 KiB
references/usage.md29.2 KiB
references/vue-js.md13.4 KiB

references/EXAMPLE-javascript-node.md

PostHog javascript-node Example Project

Repository: https://github.com/PostHog/context-mill Path: example-apps/javascript-node

README.md

PostHog Node.js Example - Todo API

A simple Express server demonstrating PostHog Node.js integration for server-side applications (APIs, backends, workers, etc.).

Purpose

This example serves as:

Verification that the context-mill wizard works for plain Node.js projects
Reference implementation of PostHog best practices for server-side Node.js code
Working example you can run and modify

Features

Event capture – tracks user actions with posthog.capture() on each route
User identification – calls posthog.identify() on write actions to associate user traits
Feature flags – gates the stats endpoint detail level with posthog.isFeatureEnabled()
Error tracking – captures exceptions with posthog.captureException() and enableExceptionAutocapture
Graceful shutdown – flushes pending events with await posthog.shutdown() on SIGINT/SIGTERM

Quick start

1. Install Dependencies

npm install

2. Configure PostHog

# Copy environment template
cp .env.example .env

# Edit .env and add your PostHog project token
# POSTHOG_PROJECT_TOKEN=phc_your_project_token_here
# POSTHOG_HOST=https://us.i.posthog.com

3. Run the server

npm start
# Todo API running at http://localhost:3000

4. Try it out

# Add a todo
curl -X POST http://localhost:3000/todos \
  -H 'Content-Type: application/json' \
  -d '{"text": "Buy groceries", "user_id": "user_123"}'

# List all todos
curl http://localhost:3000/todos

# Complete a todo
curl -X PATCH http://localhost:3000/todos/1/complete \
  -H 'Content-Type: application/json' \
  -d '{"user_id": "user_123"}'

# Delete a todo
curl -X DELETE http://localhost:3000/todos/1

# Show statistics
curl http://localhost:3000/stats

What gets tracked

The app tracks these events in PostHog:

Event	Properties	Purpose
`todo_added`	`todo_id`, `todo_length`, `total_todos`	When a todo is created
`todos_viewed`	`total_todos`, `completed_todos`	When todos are listed
`todo_completed`	`todo_id`, `time_to_complete_hours`	When a todo is completed
`todo_deleted`	`todo_id`, `was_completed`	When a todo is deleted
`stats_viewed`	`total_todos`, `completed_todos`, `pending_todos`	When stats are requested

Code structure

example-apps/javascript-node/
├── todo.js              # Express server with PostHog tracking
├── package.json         # Node.js dependencies
├── .env.example         # Environment variable template
├── .gitignore           # Git ignore rules
└── README.md            # This file

Patterns

1. Instance-based initialization

import { PostHog } from 'posthog-node';

const posthog = new PostHog(apiKey, {
  host: 'https://us.i.posthog.com',
});

2. Event tracking on routes

app.post('/todos', (req, res) => {
  // ... create todo ...

  posthog.capture({
    distinctId: req.body.user_id,
    event: 'todo_added',
    properties: { todo_id: todo.id },
  });

  res.status(201).json(todo);
});

3. Graceful shutdown

async function shutdown() {
  server.close();
  await posthog.shutdown(); // Flush pending events
  process.exit(0);
}

process.on('SIGINT', shutdown);
process.on('SIGTERM', shutdown);

Learn more

.env.example

# PostHog Configuration
POSTHOG_PROJECT_TOKEN=phc_your_project_token_here
POSTHOG_HOST=https://us.i.posthog.com

# Optional: Enable debug mode to see PostHog requests
# POSTHOG_DEBUG=true

todo.js

/**
 * Simple Todo API with PostHog Analytics
 *
 * A minimal Express server demonstrating PostHog Node.js integration
 * for server-side applications (APIs, backends, workers, etc.).
 */

import express from 'express';
import { PostHog } from 'posthog-node';
import dotenv from 'dotenv';

// Load environment variables
dotenv.config();

const app = express();
app.use(express.json());

// In-memory store, replaced with a database in production
const todos = [];
let nextId = 1;

// --- PostHog Setup ---

function initializePosthog() {
  const projectToken = process.env.POSTHOG_PROJECT_TOKEN;

  if (!projectToken) {
    console.log('WARNING: PostHog not configured (POSTHOG_PROJECT_TOKEN not set)');
    console.log('         App will work but analytics won\'t be tracked');
    return null;
  }

  const client = new PostHog(projectToken, {
    host: process.env.POSTHOG_HOST || 'https://us.i.posthog.com',
    enableExceptionAutocapture: true,
  });

  if (process.env.POSTHOG_DEBUG === 'true') {
    client.debug();
  }

  return client;
}

const posthog = initializePosthog();

function trackEvent(distinctId, event, properties = {}) {
  if (!posthog) return;

  posthog.capture({
    distinctId,
    event,
    properties,
  });
}

function identifyUser(distinctId, properties = {}) {
  if (!posthog) return;

  posthog.identify({
    distinctId,
    properties,
  });
}

// --- Routes ---

// Add a todo
app.post('/todos', (req, res) => {
  const { text, user_id } = req.body;

  if (!text) {
    return res.status(400).json({ error: 'text is required' });
  }

  const userId = user_id || 'anonymous';

  const todo = {
    id: nextId++,
    text,
    completed: false,
    created_at: new Date().toISOString(),
  };

  todos.push(todo);

  identifyUser(userId, {
    last_active: new Date().toISOString(),
    total_todos_created: todos.length,
  });

  trackEvent(userId, 'todo_added', {
    todo_id: todo.id,
    todo_length: text.length,
    total_todos: todos.length,
  });

  res.status(201).json(todo);
});

// List all todos
app.get('/todos', (req, res) => {
  const userId = req.query.user_id || 'anonymous';

  trackEvent(userId, 'todos_viewed', {
    total_todos: todos.length,
    completed_todos: todos.filter((t) => t.completed).length,
  });

  res.json(todos);
});

// Complete a todo
app.patch('/todos/:id/complete', (req, res) => {
  const todo = todos.find((t) => t.id === parseInt(req.params.id, 10));

  if (!todo) {
    return res.status(404).json({ error: 'Todo not found' });
  }

  if (todo.completed) {
    return res.status(400).json({ error: 'Todo already completed' });
  }

  todo.completed = true;
  todo.completed_at = new Date().toISOString();

  const userId = req.body.user_id || 'anonymous';

  trackEvent(userId, 'todo_completed', {
    todo_id: todo.id,
    time_to_complete_hours:
      (new Date(todo.completed_at) - new Date(todo.created_at)) / 3600000,
  });

  res.json(todo);
});

// Delete a todo
app.delete('/todos/:id', (req, res) => {
  const index = todos.findIndex((t) => t.id === parseInt(req.params.id, 10));

  if (index === -1) {
    return res.status(404).json({ error: 'Todo not found' });
  }

  const todo = todos[index];
  todos.splice(index, 1);

  const userId = req.query.user_id || 'anonymous';

  trackEvent(userId, 'todo_deleted', {
    todo_id: todo.id,
    was_completed: todo.completed,
  });

  res.status(204).end();
});

// Stats — uses a feature flag to gate detailed response
app.get('/stats', async (req, res) => {
  const total = todos.length;
  const completed = todos.filter((t) => t.completed).length;
  const pending = total - completed;

  const userId = req.query.user_id || 'anonymous';

  const stats = {
    total,
    completed,
    pending,
    completion_rate: total > 0 ? ((completed / total) * 100).toFixed(1) : '0.0',
  };

  // Check feature flag to decide whether to include per-todo breakdown
  if (posthog) {
    const showDetailed = await posthog.isFeatureEnabled(
      'detailed-analytics',
      userId,
    );

    if (showDetailed) {
      stats.todos = todos.map((t) => ({
        id: t.id,
        completed: t.completed,
        age_hours: (Date.now() - new Date(t.created_at)) / 3600000,
      }));
    }
  }

  trackEvent(userId, 'stats_viewed', {
    total_todos: total,
    completed_todos: completed,
    pending_todos: pending,
  });

  res.json(stats);
});

// --- Error Handling ---

// Global error handler — capture exceptions to PostHog
app.use((err, req, res, _next) => {
  const userId = req.body?.user_id || req.query?.user_id || 'anonymous';

  if (posthog) {
    posthog.captureException(err, userId);
  }

  console.error('Unhandled error:', err.message);
  res.status(500).json({ error: 'Internal server error' });
});

// --- Server ---

const PORT = process.env.PORT || 3000;

const server = app.listen(PORT, () => {
  console.log(`Todo API running at http://localhost:${PORT}`);
});

// Graceful shutdown, flush PostHog events before exiting
async function shutdown() {
  console.log('\nShutting down...');
  server.close();
  if (posthog) {
    await posthog.shutdown();
  }
  process.exit(0);
}

process.on('SIGINT', shutdown);
process.on('SIGTERM', shutdown);

Requirements and compatibility

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Needs: Needs an MCP server, Needs Python, Needs Node.js

Security

What our scanner noticed· Low risk

Instructions that use the network

A static scan is not a guarantee. Skills are third-party content: review a skill before you let an agent use it.

Attribution and licence

Created by

PostHog

Publisher

PostHog (Official)

Source

PostHog/skills · skills/omnibus/instrument-integration · commit a5d30e7

Licence

MIT License (redistribution allowed)

LICENSE (added by AutoGineer from LICENSE)
ATTRIBUTION.md (written by AutoGineer)

Synced

2026-11-09

AutoGineer is not affiliated with or endorsed by PostHog or PostHog.

Download ZIP

The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download instrument-integration.zip