kos.com website review

About 327 KiB of JavaScript is downloaded but never used on this page. Google estimates it would make the page about 1.7 s faster on a phone.

19 images could be 781 KiB smaller with modern formats (WebP or AVIF) and sizes that fit a phone screen. Google estimates it would make the page about 600 ms faster on a phone.

Your mobile performance score is 63. Pages that score under 90 lose visitors before the first paint.

8 third-party services load with your homepage (Klaviyo, Accessibe Accessibility Overlay and Google Tag Manager and others), adding 1.2 MB and 457 ms of main-thread time.

10 files are served with short cache lifetimes, so returning visitors download them again (106 KiB).

A phone's processor spends 3.4 s on main-thread work while loading, 1.2 s of it running JavaScript. Above 2 s, taps and scrolls feel sluggish.

Klaviyo costs a phone 159 ms of main-thread work and 315 KiB of downloads while your page loads. Loading it after the page is usable, or only on the pages that need it, takes that off the critical path.

Shopify costs a phone 49 ms of main-thread work and 438 KiB of downloads while your page loads. Loading it after the page is usable, or only on the pages that need it, takes that off the critical path.

Polyfills for old browsers add 19 KiB JavaScript that modern phones do not need. Google estimates it would make the page about 150 ms faster on a phone.

About 11 KiB of CSS is downloaded but never applied on this page. Google estimates it would make the page about 150 ms faster on a phone.

7 files block the first paint until they finish downloading. Deferring or inlining them could save about 150 ms.

3 long tasks block the main thread while loading, the longest for 131 ms. During a long task the page ignores taps.

Critical files load one after another instead of in parallel (3 chains). Preconnecting to key origins and preloading the hero image shortens the chain.

Scripts make the browser recalculate the layout repeatedly while the page loads, which wastes processor time on phones.

Real Chrome users on phones do not pass Google's Core Web Vitals on this page (28-day field data from the Chrome UX Report (opens in a new tab)). Google uses this in ranking.

Your largest element takes 12.3 s to render on a phone. Google's threshold for “good” is 2.5 s. The largest element is the element shown below.

The page becomes fully interactive after 13.5 s. Good is under 3.8 s.

Visually, the page fills in at 9.3 s (Speed Index). Good is under 3.4 s.

Real visitors see the first content after 1.8 s (75th percentile). Good is under 1.8 s.

Real visitors wait 886 ms for your server to start answering (75th percentile). Good is under 800 ms.

The first text or image appears after 2.4 s on a phone. Good is under 1.8 s.

Over the last 25 four-week periods to 2026-10-31, real Chrome visitors' largest content (lcp) went from 1.6 s to 1.6 s at the 75th percentile (Chrome UX Report (opens in a new tab) history).

Your homepage downloads 11.0 MB in 393 requests on a phone: media 6.9 MB (2), other files 1.4 MB (263) and images 1.4 MB (27). Under 2 MB keeps phones on slow connections fast.

4 images are downloaded at several times the size a phone draws them, for example VPP-VN28_d6894f73-94fa-43d1-91b6-24f5e4bfd8b6.png at 800 px wide, shown at 215 px. Resized copies would save about 94 KiB.

By the Sustainable Web Design model, a visit to your homepage emits about 3.11 g of CO₂e: 373.4 kg a year at 10,000 visits a month. It scales with page weight, so every byte cut lowers it.

1 text element doesn't have enough contrast against the background to read easily, especially outdoors on a phone.

Scrollable region must have keyboard access: 1 element on the page fails this check, rated serious by axe-core.

1 image has no alt text, which hurts accessibility and image search.

All page content should be contained by landmarks: 2 elements on the page fail this check, rated moderate by axe-core.

14 visible links have no text or label, so screen readers cannot say where they go.

No favicon is declared in the HTML, so browser tabs and Google's mobile results may show a generic icon.

The homepage links to 67 pages on kos.com and 7 external pages.

There is no Organization (or LocalBusiness) JSON-LD, so search engines and AI assistants have no machine-readable facts about who runs the site: its name, logo, profiles and contact details.

https://kos.com/products/kos-organic-plant-protein-vanilla-28-servings and https://kos.com/products/kos-organic-vegan-plant-based-protein-powder all use the title “KOS Amazing Tasting Organic Vegan Plant Based Protein Powder – KOS.com”. Search engines can't tell which page to show for a search, so each competes with the others.

https://kos.com/collections/all, https://kos.com/collections/best-sellers, https://kos.com/collections/protein, https://kos.com/collections/daily-essentials, https://kos.com/collections/brain-body-performance and https://kos.com/collections/superfood-staples and 2 others have no meta description, so Google writes the search snippet from whatever text it finds.

We fetched 15 pages linked from your homepage (of 36 found) and read each the way a search engine does.

The page uses 1 deprecated browser API that will stop working in future browsers (“Unload event listeners are deprecated and will be removed.”).

2 errors were logged to the browser console while the page loaded, for example “Failed to load resource: net::ERR_FAILED”.

Requests the notification permission on page load.

The homepage carries about 1,149 words of visible text.

Before a visitor clicks anything, the page loads Google Tag Manager and Klaviyo (measured from a US location before any click). No consent tool was detected. Visitors from the EU, UK and several US states must be asked first.

Opening the homepage sets 4 cookies (measured from a US location before any click).

No known cookie consent tool loads with the page. Some sites build their own banner, and some only show one to visitors from the EU.

Loading the homepage contacts 21 hosts run by other companies (fonts, scripts, analytics, ads), each of which sees the visitor's IP address.