Klaviyo reviews take 4–5 seconds to appear

Hi Deon,
Thank you for sharing that context, I am happy to step in here!
I went ahead and reviewed your site and observed the same slight delay for reviews to appear.

This looks like delayed client-side widget initialization, not missing review data. Our internal guidance notes that review ratings must wait for klaviyo.js and then make another request. A 4–5 second mobile delay is likely being amplified by script priority, duplicate scripts, optimization tools, or third-party apps. 

My review:

• Not seeing any duplicate klaviyo.js scripts on your site, only the one needed
• Not seeing any onsite.js or widget.js outdated/legacy snippets either 
• Klaviyo support recommends allowing klaviyo.js through performance optimizers and consent tools, and avoiding custom lazy loaders or tag-manager configurations for it.
• Other third-party widgets could interfere with the review widget’s ability to insert itself; loading those apps later was suggested as a workaround.

These widgets typically work by: the base page loads first, then the widget's own JavaScript initializes, then that JavaScript calls out to the app's backend to fetch the actual review data, and only then does it render the stars/text/images into the page. That fetch‑then‑render handoff is what creates a visible gap between "page loaded" and "reviews appear," rather than reviews showing up instantly as part of the initial HTML.

The page is also competing for bandwidth with a lot of other network activity, which can push that widget's work later in the queue. When reviewing the network traffic on this page there were: around 80 separate JavaScript and CSS files being pulled in for Shopify's checkout bundle (this is Shopify's speculative "preload the checkout" behavior, not something unique to the reviews page), repeated analytics beacons to Microsoft Clarity (e.clarity.ms), a Klaviyo tracking call, and Shopify's own telemetry endpoints (monorail-edge/otlp). None of these block the review widget outright, but on a page with that much simultaneous network and script activity, a client-side widget that has to wait its turn to fetch and render data can easily end up taking a few seconds, especially on a slower connection.

Potential fixing: 

• Exclude Klaviyo Reviews scripts from JavaScript deferral, lazy-loading, script combination, and consent blocking.
• Temporarily disable other third-party widgets one at a time and retest on a real mobile device.
• Render the average rating and review count from Shopify/Klaviyo metafields above the fold. This can appear with the page instead of waiting for the live widget, although the full review list will still require the widget.
• Add a reserved-height loading state such as “Reviews loading…” so the section does not look empty.

If the issue persists despite these recommendations, please capture a failing mobile HAR and browser-console screenshot to help us to investigate further and open a ticket as needed! 

Hi Meghan, Thanks for checking and confirming there are no duplicate or legacy scripts.

One important finding from our testing: on the same iPhone 12 Pro Max, reviews took 4–5 seconds in Safari but loaded almost instantly in Chrome. Disabling content blockers for our site in Safari made the reviews load promptly too. The delay was similar on Wi-Fi and mobile data.

Does this point to a specific Klaviyo request being affected by content blocking? Is there a supported way to make the reviews load reliably without visitors having to disable their blockers?

If you recommend rendering ratings through metafields, please provide the exact field names and confirm that they are populated and supported by Klaviyo Reviews.

Thanks, Deon