Klaviyo integration: server-side events resolved to a known profile

What Klaviyo is

Klaviyo is the email and SMS platform most DTC brands run retention on: flows, campaigns, segmentation and the revenue attribution that comes with them.

Klaviyo can only message a profile it knows about. Every anonymous session is an abandonment flow that never fires, which is why the size of your identified audience sets the ceiling on flow revenue.

How Klaviyo works

Klaviyo is built around the profile. Every event it receives is attached to a profile keyed on email or phone; if neither is present and no existing profile matches, there is nothing to attach the event to. Flows are triggered by metrics (Started Checkout, Viewed Product, Placed Order) and branch on profile properties and event data. Campaigns target segments built from those same properties. Revenue attribution works by tying a Placed Order event back to the message that preceded it. The chain only holds if the profile existed at the moment the behavior happened.

01

Recover the carts you couldn’t email

Anonymous browsers are resolved to a known profile before events reach Klaviyo, so abandonment and browse flows can fire for visitors Klaviyo never identified. The flows don’t change. The audience they can reach does.

02

Profiles, not sessions

Events arrive attached to a resolved customer, so segmentation and flow logic operate on a person rather than a device. A phone browse and a desktop purchase stop being two people.

03

Attribution that reconciles

The same resolved order powers Klaviyo’s revenue attribution and the conversions sent to your ad platforms, so the two reports stop disagreeing about the same month.

Metrics your flows can trigger on

Viewed Product, Added to Cart, Checkout Started and Placed Order arrive with " - Upstackified" added to the name by default, so they sit beside Klaviyo’s own metrics. Active on Site - Upstackified is the fourth flow trigger. Turn on Use Standard Event Names to drop the suffix.

The email attached before the event is sent

When the pixel sees an anonymous add to cart, identity resolution tries to match the session to a known customer using cookies, click IDs and cross-session behavior, and attaches the email before the event goes to Klaviyo. A click on a Klaviyo email link is a deterministic match.

Profile properties

Upstack syncs $first_name, $last_name, $city and $region plus custom identity properties to the profile, ready for segmentation as soon as they sync.

Upstack flows beside your own

The Upstack team clones your browse, cart, checkout and site abandonment flows as " - Upstack Data" copies triggered by the Upstackified metrics. Each copy waits 30 minutes longer than the original, and a 7-day exclusion means nobody gets both. Your existing flows stay as they are.

Why Klaviyo misses visitors

Shoppers switch devices, Safari and most iOS browsers expire first-party cookies set by JavaScript within 7 days, in-app browsers hand off to the default browser, and ad blockers stop Klaviyo’s own script.

Timing

Events appear in Klaviyo within a few minutes of storefront activity. Flow setup typically takes 48 to 72 hours, profiles enter the Upstack flows within 24 hours of going live, and meaningful revenue data takes 7 to 14 days.

How to verify it’s working

• Upstack’s Destinations page shows Klaviyo as Healthy.
• Klaviyo’s Analytics, Metrics page lists the Upstackified metrics within a few minutes of live traffic.
• A profile’s Activity Feed in Klaviyo shows the Upstack events for that visitor.
• Over the first 24 to 48 hours, the Analytics tab of each Upstack flow copy shows profiles entering it.
• Links in a test email carry up_kprofile_id, utm_campaign and utm_id.

Common problems and fixes

Events show in Upstack but not in Klaviyo.

Read-only keys can’t receive events. Check the key’s permissions, search Metrics for "Upstackified" in case the name differs, and reconnect with a fresh key if the destination isn’t Healthy.

Customers get two abandonment emails.

Both flows need the exclusion "received email zero times in the last 7 days where Flow is the other flow", with names that match exactly. Turn off abandonment flows left by Elevar or Triple Whale.

Duplicate events from Klaviyo’s native integration.

Turn off the native metrics Upstack also sends (Viewed Product, Added to Cart, Started Checkout, Placed Order) and keep the rest.

Low volume in the Upstack flows.

Expected in the first few days. If it is still low after two weeks, check that no other tool is running conflicting flows.

Many profiles excluded from the Upstack copy.

That means overlap with your original flow. Extend the delay to 45 or 60 minutes.

Flows aren’t sending.

Set both the original and the Upstack flow to Live, and match each email step’s status to the original’s.