Debug Klaviyo in Chrome DevTools

What Klaviyo traffic looks like

Klaviyo's traffic is identity-first: a public API key in every call, and several paths from anonymous browser to known profile.

Endpoint pattern

Onsite script from static.klaviyo.com, typically onsite/js/klaviyo.js?company_id=<six-char key>; tracking calls to a.klaviyo.com; sign-up form assets from static.klaviyo.com with form-related tracking on static-tracking.klaviyo.com

Transport

Two shapes by integration age: legacy track/identify endpoints carry the payload as a base64-encoded data parameter (decoded, it is JSON with the token, which is the same public key, plus the event name, customer_properties, and properties); newer client API calls under a.klaviyo.com/client/ send company_id in the query with a JSON body

Built-in events

Active on Site fires when an identifiable visitor browses; e-commerce integrations typically send Viewed Product and Added to Cart with full product payloads

Cookies

__kla_id holds the visitor identity; visitors arriving from Klaviyo emails carry an exchange ID (commonly a _kx URL parameter) linking the browser to a known profile without a form fill. A form submission is the other main path from anonymous to identified

The legacy data parameter decoded, as Event Watcher shows it:

{
  "token": "AbC123",
  "event": "Added to Cart",
  "customer_properties": { "$email": "user@example.dk" },
  "properties": { "ItemName": "Trail Runner", "Price": 499, "Currency": "DKK" }
}

Debugging Klaviyo with Event Watcher

• Every script load, track call, and form beacon appears in the live stream with name, icon, and category badge.
• No dedicated Klaviyo parser: requests display their parsed query and body parameters rather than decoded sections; for legacy base64 data payloads, copy the event (JSON export) and decode the parameter to inspect it.
• The cookies section shows __kla_id set/sent per request, and every call gets the consent check.

Klaviyo and consent

The extension checks Klaviyo against the marketing consent category. The sharp edge is email-click identification: a visitor landing from a campaign link can be identified via the exchange ID before touching the cookie banner.

When the script is not gated by the CMP, a pre-consent Active on Site or Viewed Product event is the default failure mode, marked pre-consent and totaled in the violations counter.

Weightier than a generic analytics ping: Klaviyo events are profile-bound.

Common debugging scenarios

• Viewed Product not populating flows. Filter to Klaviyo on a product page and confirm the track call fires with the product payload. On Shopify-style storefronts, missing events usually mean the integration snippet is absent from the theme.
• Profiles not being identified. Land on the site through a real campaign link and verify the exchange ID reaches a.klaviyo.com. Check __kla_id in the cookies section before and after.
• Duplicate or ghost events. Use the Script Tree view to see whether klaviyo.js is loaded both from the theme and from a tag manager, a common double-install.
• Pre-consent tracking from email arrivals. Replay the email-landing path with the CMP undecided and read the consent badges on the resulting events.
• Cross-checking the e-commerce stack. Pivot Grouped view by Tool to line Klaviyo events up against Mailchimp or HubSpot when several lifecycle tools claim the same conversions.