E-commerce Funnel Analysis | GA4 + BigQuery + Tableau

I created a comprehensive analytical e-commerce funnel dashboard using a sample GA4 data.
Project goal:
To help the marketing manager understand how users move through the purchase funnel and identify at which stage the largest loss of conversions occurs.
What I did:
• Retrieved and transformed GA4 data in BigQuery using SQL (CTE, JOIN)
• Built a session-level dataset with key funnel stages
• Developed an interactive dashboard in Tableau Public
• Implemented filters by date, traffic source, campaign, device, OS, and language
• Visualized the entire funnel — from the start of the session to the purchase
Key insights:
• The largest user drop-off occurs at the add-to-cart stage
• Not all traffic sources that bring sessions generate purchases
• Funnel effectiveness varies significantly depending on the traffic channel and device type
Technology stack:
SQL (BigQuery), GA4, Tableau Public