Set Up PostHog for GTM Tracking

Prerequisites

• PostHog account (cloud or self-hosted)
• Access to your application codebase

Steps

1. Create a project. Use the PostHog API or dashboard to create a new project named after your product. For separate staging/production environments, create one project per environment. Retrieve the project API key via GET /api/organizations/<org-id>/projects/ or from project settings.

2. Install the SDK. Add PostHog to your application:

   • Web: npm install posthog-js and initialize at your app entry point:

     posthog.init('<project-api-key>', { api_host: 'https://app.posthog.com' })
     

   • Node: npm install posthog-node and initialize with project API key.
   • Python: pip install posthog and set posthog.project_api_key = '<key>'.

3. Configure autocapture. PostHog autocaptures pageviews, form submissions, and interactions by default. To reduce noise, pass config options during init:

   posthog.init('<key>', { autocapture: { dom_event_allowlist: ['submit'] } })
   

   Keep pageviews and form submissions enabled -- they power funnel analysis.

4. Set up user identification. Call posthog.identify(userId) after login with a stable user ID (not email). Pass user properties:

   posthog.identify(userId, { plan: 'pro', signup_date: '2025-01-15', company: 'Acme', role: 'founder' })
   

   This links anonymous pre-signup activity to the identified user for full-journey visibility.

5. Configure group analytics. For B2B account-level analysis:

   posthog.group('company', companyId, { name: 'Acme', plan: 'enterprise', employee_count: 150 })
   

   This enables analyzing behavior at the account level, not just per-user.

6. Verify data flow. Use the PostHog MCP query_events operation or the API (GET /api/projects/<id>/events/?limit=10) to confirm events are arriving. Verify pageviews and identify calls appear with correct user properties in the properties object.