GA4 for E-Shops: Why You Need It and How to Set It Up Right

What is GA4 and why should you care

Google Analytics 4 isn’t just a “new version” of the old Google Analytics. It’s a completely rebuilt tool that measures user behavior differently — through events instead of pageviews. And that’s exactly why e-shops need it more than anyone else.

Universal Analytics (the old one) measured page visits. GA4 measures actions — what people actually do. Clicking on a product, adding to cart, starting checkout, completing a purchase. Every step is an event, and you can see exactly where customers drop off.

For an e-shop, this means one thing: you stop guessing and start knowing. How many people add a product to cart but never complete the order? Which products generate the most revenue from organic search? What’s the average order value from Meta ads vs. Google Ads?

Why you need GA4 right now

Universal Analytics stopped collecting data in July 2023. If you switched to GA4 “just because” — installed the tracking code and forgot about it — you’re probably missing critical information.

5 reasons GA4 is not optional

1. You see the full customer journey. GA4 tracks users across devices and sessions. A customer who views a product on mobile and buys it the next day on desktop is one person in GA4 — not two isolated visits.

2. E-commerce reporting on steroids. Purchase funnel, product performance, cart behavior, conversion rates by channel — all in one place. And if standard reports aren’t enough, explorations give you answers to questions you didn’t even know how to ask.

3. Integration with ad platforms. GA4 sends conversion data back to Google Ads, including order value. The algorithm optimizes campaigns more precisely — and you get more for the same budget.

4. Predictive metrics. GA4 can predict which users are likely to purchase in the next 7 days. You can then target these segments with remarketing campaigns.

5. Cookie-less future ready. GA4 is built for a world without third-party cookies. It uses data modeling and Google Signals so you don’t lose data even after cookies disappear.

How to set up GA4 for your e-shop step by step

Step 1: Create a GA4 property and install the tag

If you don’t have GA4 yet, go to analytics.google.com and create a new property. We recommend installing via Google Tag Manager (GTM) — it gives you the flexibility to add and modify events without touching the website code.

In GTM, create a tag of type “Google Analytics: GA4 Configuration” with your Measurement ID (G-XXXXXXX). Set the trigger to “All Pages”. Done — basic measurement is running.

Step 2: Set up e-commerce events

This is where it gets real. GA4 needs specific events for e-commerce reports to work. Key events:

• view_item — product view
• add_to_cart — adding to cart
• begin_checkout — starting the checkout
• purchase — order completion (with value and items)
• view_item_list — category/product listing view
• select_item — clicking a product in a listing

Each event must contain the correct parameters — currency, value, items[] with item_id, item_name, and price. Without them, GA4 will record the events, but e-commerce reports will be empty.

Step 3: Mark key events as conversions

In GA4, go to Admin → Events and toggle “Mark as key event” for purchase, begin_checkout, and optionally add_to_cart. Only then will they appear in conversion reports and send data to Google Ads.

Step 4: Connect GA4 with Google Ads

In GA4, go to Admin → Product links → Google Ads and link your accounts. Import key events into Google Ads as conversions. This lets the algorithms optimize for actual purchases with real values — not just clicks.

Step 5: Set up custom dimensions and metrics

Standard events cover the basics, but for deeper analysis, add custom parameters:

• payment_method — card vs. cash on delivery
• shipping_method — delivery method
• coupon_used — whether the customer used a discount code
• customer_type — new vs. returning customer

Register these parameters in GA4 as custom dimensions (Admin → Custom definitions), otherwise the data is sent but won’t appear in reports.

4 reports every e-shop must track

1. Purchase journey

Monetization → Purchase journey shows your conversion funnel: how many people viewed a product → added to cart → started checkout → purchased. At each step, you see the drop-off rate. If 70% of people drop between cart and checkout, you have a clear problem to solve.

2. Product performance

Monetization → E-commerce purchases displays revenue, number of sales, and conversion rate for each product. Sort by conversion rate and you’ll find products with high conversion (maybe they just need more traffic) and those with low conversion (maybe they need a better page).

3. Acquisition by channel

Acquisition → Traffic acquisition shows where visitors come from and how many of them buy. Compare the ROAS of organic search, paid ads, social media, and email. You might discover that email marketing with 0 acquisition cost generates 25% of revenue.

4. Explorations — custom analyses

Explore → Free form is GA4’s most powerful tool. You can build any analysis from available dimensions and metrics. Example: “Revenue by traffic source × product category × device” — and suddenly you see that mobile from Meta ads sells mainly one category, while Google Ads desktop sells others.

Common GA4 setup mistakes for e-shops

Missing value in purchase event. If the purchase event doesn’t contain the value and currency parameters, GA4 records the conversion but with zero value. Ad platforms can’t optimize for ROAS.

Duplicate events. If you have a GA4 tag in GTM and also directly in the website code (or via a plugin), every event fires twice. Result: doubled conversions, inflated revenue, skewed data. Always use just one implementation method.

Unregistered custom parameters. You’re sending data, but can’t see it in reports. Every custom parameter must be manually registered as a custom dimension/metric in GA4’s admin section.

Missing cross-domain tracking. If your e-shop uses a payment gateway on a different domain (and the customer is redirected), GA4 without cross-domain tracking treats it as a new visit from a referral source. The original acquisition source is lost.

Ignoring consent mode. In the EU, you must respect GDPR. Without proper Google Consent Mode v2, you lose data from users who decline cookies. GA4 does model missing data, but only if consent mode is properly implemented.

Pro tips from practice

Set up audience triggers. Create a segment “added to cart but didn’t buy in the last 7 days” and automatically export it to Google Ads as a remarketing segment. These campaigns typically have 3–5x higher conversion rate than cold traffic.

Use Debug View. GA4 has a built-in Debug View (Admin → DebugView) where you see events in real time. Before launching a campaign, always verify that the purchase event sends the correct data — value, currency, and item list.

Connect GA4 with BigQuery. GA4 offers free raw data export to BigQuery. For larger e-shops, this is a game-changer — you can analyze cohort behavior, customer lifetime value, and build predictive models that you simply can’t do in the GA4 interface.