serenium.co website review

6 files block the first paint until they finish downloading. Deferring or inlining them could save about 1.1 s.

A phone's processor spends 5.5 s on main-thread work while loading, 2.9 s of it running JavaScript. Above 2 s, taps and scrolls feel sluggish.

8 third-party services load with your homepage (Google Tag Manager, alia-prod.com and Shopify and others), adding 2.3 MB and 1.4 s of main-thread time.

About 946 KiB of JavaScript is downloaded but never used on this page. Google estimates it would make the page about 300 ms faster on a phone.

Your mobile performance score is 65. Pages that score under 90 lose visitors before the first paint.

Google Tag Manager costs a phone 412 ms of main-thread work and 641 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.

17 files are served with short cache lifetimes, so returning visitors download them again (347 KiB).

alia-prod.com costs a phone 257 ms of main-thread work and 255 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 203 ms of main-thread work and 762 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.

13 long tasks block the main thread while loading, the longest for 269 ms. During a long task the page ignores taps.

rebuyengine.com costs a phone 127 ms of main-thread work and 332 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.

About 90 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.

Polyfills for old browsers add 78 KiB JavaScript that modern phones do not need.

5 images could be 47 KiB smaller with modern formats (WebP or AVIF) and sizes that fit a phone screen.

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.

The page becomes fully interactive after 23.5 s. Good is under 3.8 s.

Your largest element takes 4.8 s to render on a phone. Google's threshold for “good” is 2.5 s. The largest element is the image.

Over the last 25 four-week periods to 2026-10-31, real Chrome visitors' tap response (inp) went from 157 ms to 189 ms at the 75th percentile (Chrome UX Report (opens in a new tab) history).

Visually, the page fills in at 5.2 s (Speed Index). Good is under 3.4 s.

Scripts block taps and scrolling for 479 ms in total while the page loads. Good is under 200 ms.

The first text or image appears after 2.0 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 3.1 s to 3.2 s at the 75th percentile (Chrome UX Report (opens in a new tab) history).

Your homepage downloads 4.6 MB in 438 requests on a phone: scripts 2.3 MB (94), other files 1.5 MB (292) and images 556 KiB (36). Under 2 MB keeps phones on slow connections fast.

2 images further down the page (49 KiB) download before anyone scrolls to them. Adding loading="lazy" lets the first screen load first.

By the Sustainable Web Design model, a visit to your homepage emits about 1.31 g of CO₂e: 157.1 kg a year at 10,000 visits a month. It scales with page weight, so every byte cut lowers it.

4 tap targets are too small or too close together to hit reliably with a finger.

Scrollable region must have keyboard access: 2 elements on the page fail this check, rated serious by axe-core.

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

All page content should be contained by landmarks: 5 elements on the page fail this check, rated moderate by axe-core.

The viewport tag blocks pinch-zoom, which low-vision visitors rely on.

No meta description, so Google writes its own snippet from whatever text it finds.

Your title is only 8 characters: “Serenium”. Between 30 and 65 characters leaves room to say what you do and for whom.

Open Graph is missing og:description, so shared links fall back to guesses.

The homepage links to 45 pages on serenium.co and 3 external pages.

Your Organization JSON-LD is missing logo, sameAs (social profiles), description and contact details. These are the facts AI assistants use to describe a business and to tell it apart from others with a similar name.

https://serenium.co/es-us/collections/mejor-vendido, https://serenium.co/es-us/pages/contactanos, https://serenium.co/es-us/policies/shipping-policy, https://serenium.co/es-us/policies/refund-policy, https://serenium.co/es-us/policies/privacy-policy and https://serenium.co/es-us/policies/terms-of-service have no meta description, so Google writes the search snippet from whatever text it finds.

https://serenium.co/es-us/collections/mejor-vendido, https://serenium.co/es-us/apps/parcelpanel and https://serenium.co/es-us/pages/contactanos have no <h1> headline, so visitors and search engines get no clear main topic.

We fetched 14 pages linked from your homepage and read each the way a search engine does.

10 of 45 tappable elements near the top of the page are smaller than 24 px, hard to hit with a thumb.

2 errors were logged to the browser console while the page loaded, for example “Error: .doubleusps element not found”.

On a phone, there is no call to action on the first screen: visitors have to scroll to find out what to do next.

We found no call-to-action buttons or links (such as “Book a demo” or “Get a quote”) anywhere on the homepage.

Social proof on the homepage: a star rating. Pairing it with named testimonials or customer logos makes it far more convincing.

No guarantee or risk reducer (money-back, free trial, no credit card) is mentioned, which is often what tips a hesitant visitor.

The homepage carries about 384 words of visible text.

Before a visitor clicks anything, the page loads Google Ads, Google Analytics, Google Tag Manager, Klaviyo and Meta Pixel and 1 more (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 28 cookies, 1 of them by other companies (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 40 hosts run by other companies (fonts, scripts, analytics, ads), each of which sees the visitor's IP address.