This case study shows how I built an end-to-end tracking and data-flow pipeline from GTM → GA4 → Zapier → HubSpot → Salesforce. It captures attribution (UTMs), user identity (client_id + session_id), form interactions, lifecycle automation, and CRM object mapping into a unified reporting system.

Lead Flow

1. Website Interaction

User loads page → GTM fires:

• GA4 tags
• Hidden input population script
• Session + client ID captured

2. GA4 Receives Signals

GA4 logs structured events:

• form_start
• form_submit
• generate_lead
• key_event (converted)

Custom parameters passed:

• client_id
• session_id
• utm_*
• landing_page

3. Zapier Webhook / GA4 Trigger