Key events in Google Analytics 4: what to measure on your website to sell more

The report says your website had 4,000 visits this month. Sounds good. But when you ask “and how many of those people messaged us on WhatsApp or booked an appointment?”, nobody can answer.

Counting visits without measuring actions is like knowing how many people walked into the store without knowing how many bought. In Google Analytics 4, what separates a pretty report from a useful one is key events.

What is a key event in GA4?

It is an event that measures an action especially important to your business's success. That is how the official Google Analytics help defines it. When it happens, it is recorded as a key event and highlighted in your reports.

The logic is a ladder:

Level	What it is	Example
Event	Any recorded interaction	Viewing a page, scrolling
Key event	An event you mark as important to your business	Click on the WhatsApp button
Conversion	A key event used in Google Ads to optimize	The campaign optimizes for WhatsApp clicks

Which key events should a service website measure?

The ones that represent a customer raising their hand. For a company that sells through conversation:

1. Click on the WhatsApp button: the most common contact in Latin America.
2. Confirmed booking: the person reserved an appointment.
3. Click to write from the pricing page or a key service page.
4. Purchase or payment, if you sell online.

Common mistake: marking scroll, time on page or every click as a key event. If everything is key, nothing is: reports fill up with noise and Google Ads optimizes toward actions that do not bring customers.

How do I mark an event as key?

From GA4's event settings: any event already being collected can be marked as a key event. According to Google, if an event is important to your business's success, mark it as a key event. First make sure the event exists (for example, that the WhatsApp click is being recorded) and then mark it.

How does this connect to my advertising?

Key events are the foundation of Google Ads conversions. Google states that conversions are created from Analytics events, to measure actions consistently across both platforms, and that you can create as many conversions as you want from key events.

With that, your campaign stops optimizing for clicks and starts optimizing for real contacts. And if you want to go one step further, toward closed sales, connect your CRM to your ads as we explain in Meta's Conversions API. To know whether that investment pays off, check ROAS and cost per lead.

Watch out: the WhatsApp click measures intent, not a sale. Use it as a key event, but always cross-check with your CRM to know how many of those chats ended in customers.

What else should I check to measure well?

• That the website loads fast: a slow page loses visits before any event is recorded. Read website speed and Core Web Vitals.
• That the buttons are clear: a key event only happens if the visitor finds the button.
• That the source is recorded: campaign, ad and channel, so you know what works.

In short

Visits count who came in; key events count who raised their hand. On a service website, measure WhatsApp clicks, bookings and payments, mark them as key events and use them as conversions in Google Ads. That way the 4,000-visit report finally answers the question that matters. We set it up in our Meta and Google Ads service.