Klaviyo web tracking: what it sees on your Shopify store, and how to check it works

Klaviyo can only follow people it already knows

Let's get the awkward bit out of the way. Klaviyo doesn't see your traffic. It sees the slice of your traffic it can put an email address or phone number to, and nobody else.

Everyone else browsing your store is a stranger to it. They can look at the same product five times and nothing gets logged against a profile, because there's no profile to log it against. Shopify knows they were there. Klaviyo doesn't.

So when a brand asks why browse emails go to so few people, the answer's usually not a broken flow. It's a small known audience, a consent banner doing its job, and a browser quietly forgetting who people are.

The events web tracking sends back from Shopify

On Shopify, tracking runs through the Klaviyo app embed in your theme. According to Klaviyo's Shopify onsite tracking guide, two events come through the embed and three more come through a Shopify pixel once you tick Track behavioral events in the integration settings.

Viewed Product is the one that matters most, because it's the trigger behind the browse abandonment flow. If that event isn't arriving, the flow has nothing to start from.

One trap worth knowing. The app embed belongs to a theme, so publish a new theme and you have to switch it on again. A redesign can go live and quietly stop every browse email.

How a visitor goes from stranger to profile

Klaviyo's onsite tracking article lists the moments a browser becomes identifiable. For most Shopify brands it comes down to two: somebody clicks through from a Klaviyo email or text, or somebody fills in a Klaviyo form.

Look at the first and third rows there. The opt in flow is fed by a pop up, and the browse flow runs on Viewed Product. The pop up is what makes the browse flow possible, because every sign up is another browser Klaviyo can now follow.

Email clicks work through a small parameter Klaviyo adds to the links in live emails. Click one and the browser gets cookied, so the next visit is recognised too, until the cookie goes.

Why browse emails reach so few people

Even once someone's known, three things stand between their browse and your flow. None of them are bugs.

1. Consent. Klaviyo says it may not track onsite events for UK, EU and Swiss visitors to a Shopify store unless they've consented, based on your Shopify Customer Privacy settings
2. Cookie lifetime. Klaviyo's tracking cookie is set by JavaScript, and Safari and Firefox cap how long a cookie like that survives, so a known shopper goes back to being a stranger
3. Devices. Someone who signed up on a laptop and browses on their phone is a new browser until they click an email on that phone

The first one you shouldn't try to get round. Tracking someone for marketing on a UK site needs a lawful basis, and the ICO's guidance on cookies is where to check your banner. Not legal advice, just the place we'd start.

The second has a partial fix. Klaviyo's First-Party ID runs a Cloudflare worker on a subdomain of your own domain and refreshes the cookie when it expires. It only re-identifies people who already have a profile, and Klaviyo suggests you re-issue your cookie notice when you turn it on.

Flows only earn on the events they can see

Flows earn while nobody's touching them. That's only true if the events feeding them turn up, and the behaviour flows are the ones that lean on web tracking hardest.

On the Shadow Foam account the flows carried most of the email revenue for the quarter. The browse and cart flows in that stack only fire because Viewed Product and Added to Cart keep arriving.

So check tracking before you rewrite a word of copy. A beautiful browse email that fires for a handful of people a week is a tracking problem wearing a design problem's clothes.

Test it yourself in five minutes

Here's the test from Klaviyo's own help centre. Give it about fifteen minutes after switching the app embed on before you start, and use a private window so an old cookie doesn't muddy it.

• Open your homepage with ?utm_email= and your own address on the end of the URL
• Reload the page, then open a product page
• Search for your address in Klaviyo and open the profile
• Look for Active on Site and Viewed Product in the activity feed
• Check Analytics, then Metrics, for both events coming in
• For Added to Cart, identify yourself with a form first, then add something

Both events there? Tracking works, and a quiet browse flow is about audience size and consent, not setup. Nothing showing? Start with the app embed on the live theme. If you'd rather someone else poked at it, that's part of what we do inside Klaviyo.