GA4 key events and recommended e-commerce events

Key events and conversions: why two words

Google Analytics Help explains the change: important events that were marked as conversions in Analytics used to be measured differently from Google Ads conversions, which led to discrepancies between the two tools. To make measurement simpler and more consistent, Google unified how conversions are defined.

The result is a clear chain: an event is anything you measure; a key event is an event you mark as important to your business in Analytics; a conversion is created from a Google Analytics event to measure important actions consistently in both Analytics and Google Ads, and is what your campaigns optimise towards.

How to mark a key event, and the limits

• Mark an existing event: in Admin, open Events, find the event under Recent events and click the star icon.
• Create one: click Create event, name it, switch on Mark as key event and save.
• Defaults: Analytics marks purchase as a key event automatically on web and app (plus first_open, in_app_purchase and app store subscription events for apps).
• Limits: up to 30 key events per standard property, 50 for Analytics 360.
• History: marking an event as key does not change historic data.
• Delay: allow up to 24 hours for a key event to appear in standard reports; Realtime shows it within minutes.
• Counting: a key event can be counted once per event or once per session.

The recommended e-commerce events

Recommended events are events whose names and parameters Google has defined in advance. They are not sent automatically: you or your developer implement them, and in return they power GA4's e-commerce reports and suggested audiences. For online sales, Google's list is:

Getting purchase right

The purchase event carries the money, so it deserves the most care. Google's e-commerce developer guide shows it with a transaction_id, a value, a currency and an items array, each item with an ID or name, a price and a quantity. Two details matter most:

• Set currency whenever you send value: Google asks for currency at event level when sending revenue, as it is the currency used for standard reporting.
• Always send a transaction ID: Google describes it as required for purchases and refunds; it identifies the order, so a refund can be matched to it.
• Fire purchase once, on confirmed payment, not on every reload of the thank-you page.

If you sell services or take enquiries

Not every business has a cart. Google's recommended events for lead generation follow a lead through its life: generate_lead when a form is submitted, then qualify_lead, disqualify_lead, working_lead, close_convert_lead and close_unconvert_lead as your team handles it. For most service businesses, generate_lead marked as a key event is the right starting point.

Which events to mark as key events

• Mark what represents business value: purchase for a shop, generate_lead for a service business, perhaps a booked call.
• Don't mark everything: page views, scrolls and add_to_cart are useful steps, but marking them as key events blurs the reports and, if imported into Google Ads, can make bidding chase the wrong goal.
• Keep the funnel events anyway: view_item, add_to_cart and begin_checkout show where people drop off, even when they are not key events.
• Test before you trust: place a test order or submit a test form, watch the event arrive in Realtime, and check the value and currency on the purchase. A key event that fires twice, or with the wrong amount, is worse than none.
• Check consent: in the European Economic Area, measurement depends on consent signals; see our guide on Consent Mode v2.

What we set up at Takat

On the 26 of our own sites that sell, GA4 is set up with a consent banner where Refuse is as easy as Accept, and with the e-commerce events add_to_cart, begin_checkout and purchase. For Meta campaigns we add the Conversions API with server-side purchase events. Measurement stays in the client's own accounts. See Tracking.