TanStack Start · Instrument Integration · PostHog/skills · Skills Docs

TanStack Start · Instrument Integration · PostHog/skills · Skills Docs

// 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: '2026-01-30',
            capture_exceptions: true
          }}
        >
          {children}
        </PostHogProvider>
        <Scripts />
      </body>
    </html>
  )
}

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>
}

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')
  }
}

// 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
}

// src/routes/api/checkout.ts
import { createFileRoute } from '@tanstack/react-router'
import { json } from '@tanstack/react-start'
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 json({ success: true })
      },
    },
  },
})