isero.nl website review

About 1.8 MB of JavaScript is downloaded but never used on this page. Google estimates it would make the page about 5.8 s faster on a phone.

1 file blocks the first paint until they finish downloading. Deferring or inlining it could save about 2.8 s.

Your mobile performance score is 31 (desktop: 33). Under 50 is Google's “poor” band: many phone visitors leave before the page is usable.

A phone's processor spends 5.7 s on main-thread work while loading, 3.8 s of it running JavaScript. Above 2 s, taps and scrolls feel sluggish.

8 third-party services load with your homepage (Google Tag Manager, trengo.eu and omappapi.com and others), adding 1.7 MB and 997 ms of main-thread time.

About 176 KiB of CSS is downloaded but never applied on this page. Google estimates it would make the page about 610 ms faster on a phone.

Google Tag Manager costs a phone 491 ms of main-thread work and 713 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.

32 files are served with short cache lifetimes, so returning visitors download them again (109 KiB).

trengo.eu costs a phone 210 ms of main-thread work and 407 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.

Google Maps costs a phone 130 ms of main-thread work and 366 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.

11 images could be 120 KiB smaller with modern formats (WebP or AVIF) and sizes that fit a phone screen. Google estimates it would make the page about 150 ms faster on a phone.

20 long tasks block the main thread while loading, the longest for 230 ms. During a long task the page ignores taps.

Web fonts hide text while they load. Setting font-display: swap shows text immediately (about 50 ms).

22 KiB could be saved by minifying CSS.

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.

The first text or image appears after 11.7 s on a phone. Good is under 1.8 s.

Your largest element takes 18.7 s to render on a phone. Google's threshold for “good” is 2.5 s. The largest element is the image “voltreffer juni banner”.

The page becomes fully interactive after 27.1 s. Good is under 3.8 s.

Visually, the page fills in at 13.2 s (Speed Index). Good is under 3.4 s.

Scripts block taps and scrolling for 1.2 s in total while the page loads. Good is under 200 ms.

Real visitors wait 244 ms for the page to respond to a tap (75th percentile). Good is under 200 ms.

For real visitors the layout shifts by 0.24 (75th percentile). Good is under 0.1.

23 images have no width and height attributes, so the layout jumps as each one loads.

Over the last 25 four-week periods to 2026-10-24, real Chrome visitors' tap response (inp) went from 260 ms to 237 ms at the 75th percentile (Chrome UX Report (opens in a new tab) history).

Your homepage downloads 4.4 MB in 175 requests on a phone: scripts 3.4 MB (58), images 339 KiB (47) and fonts 292 KiB (4). Under 2 MB keeps phones on slow connections fast.

By the Sustainable Web Design model, a visit to your homepage emits about 1.25 g of CO₂e: 149.6 kg a year at 10,000 visits a month. It scales with page weight, so every byte cut lowers it.

6 text elements don't have enough contrast against the background to read easily, especially outdoors on a phone.

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

8 buttons have no accessible name, so screen readers announce just “button”.

Heading levels should only increase by one: 1 element on the page fails this check, rated moderate by axe-core.

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

Page should contain a level-one heading: 1 element on the page fails this check, rated moderate by axe-core.

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

1 form field has no label, so screen readers announce an empty box and autofill guesses.

Alternative text of images should not be repeated as text: 3 elements on the page fail this check, rated minor by axe-core.

Elements with visible text labels do not have matching accessible names. (2 elements).

There is no <h1>, so neither visitors nor Google get a clear main headline.

Your title is 112 characters, so Google will cut it off around 60: “Isero | Dé groothandel voor hang- en sluitwerk, gereedschap, bevestigingsmiddelen en werk…”.

No structured data (JSON-LD), so Google can't show rich results such as your logo, ratings or FAQs.

No canonical URL, so duplicate versions of the homepage (with or without www, with tracking parameters) can split ranking signals.

No XML sitemap at https://www.isero.nl/sitemap.xml, so Google discovers your pages only by following links.

12 links have no real href, so search engines can't follow them.

No twitter:card tag. X falls back to Open Graph, which is set, so this is minor.

The homepage links to 173 pages on isero.nl and 6 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.

There is no https://www.isero.nl/llms.txt, a short Markdown guide to your key pages for AI tools (llmstxt.org). It is optional and few AI tools read it yet, so treat it as a cheap extra.

https://www.isero.nl/nl-nl and https://www.isero.nl/nl-nl/store-finder all use the title “Isero | Dé groothandel voor hang- en sluitwerk, gereedschap, bevestig…”. Search engines can't tell which page to show for a search, so each competes with the others.

https://www.isero.nl/nl-nl/store-finder has no <h1> headline, so visitors and search engines get no clear main topic.

https://www.isero.nl/nl-nl/store-finder has under 150 words in the HTML. Thin pages rarely rank; if the text loads with JavaScript, crawlers that don't run it see even less.

https://www.isero.nl/nl-nl/sleutels-nu, https://www.isero.nl/nl-nl/sleutelplan, https://www.isero.nl/nl-nl/bewegwijzering-binnen-buiten, https://www.isero.nl/nl-nl/deurbeslag-raambeslag-veiligheidsbeslag-sleutelplan-voor-woning-of-bedrijfspand, https://www.isero.nl/nl-nl/postkasten and https://www.isero.nl/nl-nl/mechanisch-elektronisch-sleutelbeheer and 2 others took over 3 s to send their HTML from our server.

We fetched 15 pages linked from your homepage (of 85 found) and read each the way a search engine does.

15 of 40 tappable elements near the top of the page are smaller than 24 px, hard to hit with a thumb.

Large scripts ship without source maps.

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

No testimonials, customer logos, ratings or customer counts on the homepage: nothing tells a new visitor that others already trust you.

No phone number or email link on the homepage, so ready-to-buy visitors have one fewer way to reach you.

The homepage has only about 93 words of visible text; thin pages give Google and first-time buyers little to go on.

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

Before a visitor clicks anything, the page loads Google Ads, Google Analytics and Google Tag Manager (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 6 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 15 hosts run by other companies (fonts, scripts, analytics, ads), each of which sees the visitor's IP address.