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://mp-staging.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/tanstack-start.md

AI agents: this is one page from PostHog's docs. Full index of Markdown docs for LLMs: https://posthog.com/llms.txt

TanStack Start

Canonical URL: https://posthog.com/docs/libraries/tanstack-start

Cloud region: This page uses US Cloud hosts. For an EU Cloud project, use https://eu.i.posthog.com instead of https://us.i.posthog.com (ingestion host).

Install with the wizard

Run this command in your project directory to add PostHog to your TanStack Start project. The wizard detects your framework, installs the SDK, and sets up your first events.

npx @posthog/wizard

Or set it up manually by following the rest of this guide.

Installation

Install the required packages:

npm install @posthog/react posthog-node

@posthog/react - React package for our JS Web SDK for client-side usage
posthog-node - PostHog Node.js SDK for server-side event capture

If your site sets a Content-Security-Policy, it needs to allow PostHog. This applies to the snippet and to package installs alike: the SDK lazy-loads extra bundles (session replay, surveys) from PostHog's CDN, and sends events to the ingestion host. PostHog serves from subdomains of posthog.com that change over time, so allow the wildcard:
script-src 'self' https://*.posthog.com;
connect-src 'self' https://*.posthog.com;
worker-src 'self' blob: data:;
script-src covers the snippet and the lazy-loaded bundles, connect-src covers event ingestion and feature flags, and worker-src covers session replay. The toolbar needs a few more, or use a reverse proxy so everything is first-party. Failing to do so causes silent failures where capture and identify calls never send, so the integration looks complete while zero events arrive. Remember connect-src falls back to default-src, so default-src 'self' blocks event delivery even when the script itself is bundled.

Identifying users

Identifying users is required. Call posthog.identify('your-user-id') after login to link events to a known user. This is what connects frontend event captures, session replays, LLM traces, and error tracking to the same person — and lets backend events link back too.
Use a stable ID from your auth system when possible, not an email or display name. Send those as person properties instead. If your app has no other stable key, email works as a fallback if they are unique. Never a shared literal like "anonymous" or "user", which pools many people onto one person and corrupts their data. When no ID is available at all, skip the identify and retain the anonymous distinct ID that's automatically assigned.
Call posthog.reset() on logout, so the next person to use the browser doesn't inherit the last one's identity.
See our guide on identifying users for how to set this up.

If your app calls your own backend, tracing_headers adds X-POSTHOG-DISTINCT-ID and X-POSTHOG-SESSION-ID to matching fetch and XMLHttpRequest requests. This lets server-side SDKs link backend events, errors, and LLM traces back to frontend sessions and replays. Use hostnames only, without protocols or paths.

posthog.init('<ph_project_token>', {
  api_host: 'https://us.i.posthog.com',
  // Optional: send PostHog session/user context to your backend
  tracing_headers: ['api.example.com'],
})

This works in local development too, but match on the hostname alone: use 'localhost', not 'localhost:3000'. Ports are never part of a hostname, so a value with one in it never matches anything. localhost and 127.0.0.1 are also different hostnames — use whichever your app actually calls.

Tracing headers help you attribute events across front and backend consistently. When this isn't available, use your server-side stable IDs to deduce the matching distinctId, and pass it in when capturing the event.

Initialize PostHog on the client

Wrap your app with PostHogProvider in your root route with your project token, host, and other options.

src/routes/__root.tsx

// src/routes/__root.tsx
import { HeadContent, Scripts, createRootRoute } from '@tanstack/react-router'
import { PostHogProvider } from '@posthog/react'

export const Route = createRootRoute({
  head: () => ({
    meta: [
      { charSet: 'utf-8' },
      { name: 'viewport', content: 'width=device-width, initial-scale=1' },
    ],
  }),
  shellComponent: RootDocument,
})

function RootDocument({ children }: { children: React.ReactNode }) {
  return (
    <html lang="en">
      <head>
        <HeadContent />
      </head>
      <body>
        <PostHogProvider
          apiKey="<ph_project_token>"
          options={{
            api_host: 'https://us.i.posthog.com',
            defaults: '2026-08-30',
            capture_exceptions: true
          }}
        >
          {children}
        </PostHogProvider>
        <Scripts />
      </body>
    </html>
  )
}

Once the provider is in place, PostHog automatically captures pageviews, sessions, and web vitals.

Capture events on the client

Use the usePostHog hook from @posthog/react in any component to capture custom events:

src/routes/checkout.tsx

import { usePostHog } from '@posthog/react'

function CheckoutButton({ orderId, total }: { orderId: string; total: number }) {
  const posthog = usePostHog()

  const handleClick = () => {
    posthog.capture('checkout_started', {
      order_id: orderId,
      total: total,
    })
  }

  return <button onClick={handleClick}>Checkout</button>
}

Identify users

Call posthog.identify() when a user logs in to link their events to a user ID:

import { usePostHog } from '@posthog/react'

function LoginForm() {
  const posthog = usePostHog()

  const handleLogin = async (userId: string, email: string) => {
    // ... your login logic

    posthog.identify(userId, {
      email: email,
    })

    posthog.capture('user_logged_in')
  }
}

Call posthog.reset() on logout to clear the identified user.

Initialize PostHog on the server

Create a server-side PostHog client using posthog-node. Use a singleton pattern so you reuse the same client across requests:

src/utils/posthog-server.ts

// src/utils/posthog-server.ts
import { PostHog } from 'posthog-node'

let posthogClient: PostHog | null = null

export function getPostHogClient() {
  if (!posthogClient) {
    posthogClient = new PostHog(
      '<ph_project_token>',
      {
        host: 'https://us.i.posthog.com',
        flushAt: 1,
        flushInterval: 0,
      },
    )
  }
  return posthogClient
}

Capture events on the server

Use the server client in TanStack Start API routes to capture events server-side. Server-side capture is useful for tracking events that shouldn't be spoofable from the client, like purchases or authentication:

src/routes/api/checkout.ts

// src/routes/api/checkout.ts
import { createFileRoute } from '@tanstack/react-router'
import { getPostHogClient } from '../../utils/posthog-server'

export const Route = createFileRoute('/api/checkout')({
  server: {
    handlers: {
      POST: async ({ request }) => {
        const body = await request.json()

        const posthog = getPostHogClient()

        posthog.capture({
          distinctId: body.userId,
          event: 'item_purchased',
          properties: {
            item_id: body.itemId,
            price: body.price,
            source: 'api',
          },
        })

        return Response.json({ success: true })
      },
    },
  },
})

The server-side capture call requires a distinctId (the user identifier), an event name, and optional properties.

Add request context to backend spans

For a Node.js deployment with OpenTelemetry, reuse getPostHogClient() for both request context and the span processor. Add this processor to your existing tracing provider before the server accepts requests:

import { PostHogContextSpanProcessor } from 'posthog-node/otel'
import { getPostHogClient } from './src/utils/posthog-server'

const posthogSpanProcessor = new PostHogContextSpanProcessor(getPostHogClient())

Include posthogSpanProcessor in that provider's spanProcessors configuration. Keep your existing exporter, sampler, and instrumentation. See the Node.js tracing setup for provider setup. Keep this setup on the server. Shut down the provider and the PostHog client through your application's shutdown hook, after requests finish.

Add global request middleware in src/start.ts. If that file already exists, add the middleware to its existing configuration. Keep your existing CSRF and authentication middleware. This example includes TanStack Start's CSRF middleware because defining src/start.ts replaces its default setup.

src/start.ts

import {
  createCsrfMiddleware,
  createMiddleware,
  createStart,
} from '@tanstack/react-start'
import { enrichCurrentSpan } from 'posthog-node/otel'
import { getPostHogClient } from './utils/posthog-server'

function tracingHeader(request: Request, name: string): string | undefined {
  const value = request.headers.get(name)
  return value?.replace(/[\x00-\x1f\x7f-\x9f]/g, '').trim().slice(0, 1000) || undefined
}

const posthogContext = createMiddleware().server(async ({ request, next }) => {
  const posthog = getPostHogClient()
  const existing = posthog.getContext()

  return posthog.withContext(
    {
      distinctId:
        existing?.distinctId ??
        tracingHeader(request, 'X-POSTHOG-DISTINCT-ID'),
      sessionId:
        existing?.sessionId ??
        tracingHeader(request, 'X-POSTHOG-SESSION-ID'),
    },
    async () => {
      enrichCurrentSpan(posthog)
      return await next()
    },
    { fresh: true }
  )
})

export const startInstance = createStart(() => ({
  requestMiddleware: [createCsrfMiddleware({ filter: ({ handlerType }) => handlerType === 'serverFn' }), posthogContext],
}))

This setup was checked with TanStack Start 1.169.3 on Node.js. It runs for SSR, server routes, and server functions. It reads the two browser tracing headers without copying other headers or request data. The header helper removes control characters, trims whitespace, and limits each ID to 1,000 characters. An identity already set by application code takes precedence. Treat browser IDs as analytics data, not authentication. Set authenticated identity before this middleware when you need it to take precedence.

The processor fills missing sessionId and posthogDistinctId span attributes. Explicit canonical attributes stay unchanged, including non-string values. user.id alone is not an override. At request entry, the helper also fills missing attributes on the nearest recording server ancestor whose parent chain the processor observed. A sampler-dropped intermediate breaks that chain, so the earlier server span stays unchanged.

Work that the request starts, including detached tasks, keeps the IDs after next() returns or throws. This example does not support the edge runtime. Give separately owned background work that needs its own IDs an explicit context.

TanStack handles some route and server-function errors before middleware can see them. Capture an error once at the application handler that owns it, while request context is active:

try {
  await savePurchase()
} catch (error) {
  getPostHogClient().captureException(error)
  throw error
}

Do not add a second capture if an existing error handler already reports the same error. This middleware does not enable automatic error capture.

Next steps

Installing the JS Web SDK and Node SDK means all of their functionality is available in your TanStack Start project. To learn more about this, have a look at our JS Web SDK docs and Node SDK docs.

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

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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

2026-11-08

AutoGineer is not affiliated with or endorsed by PostHog.

Download ZIP

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