trimbos.nl website review

20 files block the first paint until they finish downloading. Deferring or inlining them could save about 2.5 s.

8 third-party services load with your homepage (Google CDN, Google Tag Manager and Cookiebot and others), adding 1.8 MB and 1.3 s of main-thread time.

Your mobile performance score is 59. Pages that score under 90 lose visitors before the first paint.

About 879 KiB of JavaScript is downloaded but never used on this page. Google estimates it would make the page about 60 ms faster on a phone.

About 216 KiB of CSS is downloaded but never applied on this page. Google estimates it would make the page about 660 ms faster on a phone.

Google CDN costs a phone 640 ms of main-thread work and 1.1 MB 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.

2 images could be 67 KiB smaller with modern formats (WebP or AVIF) and sizes that fit a phone screen. Google estimates it would make the page about 500 ms faster on a phone.

Google Tag Manager costs a phone 383 ms of main-thread work and 364 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.

A phone's processor spends 3.6 s on main-thread work while loading, 1.8 s of it running JavaScript. Above 2 s, taps and scrolls feel sluggish.

The page has 2,012 HTML elements. Above 1,500, rendering and every interaction get slower on phones.

15 long tasks block the main thread while loading, the longest for 224 ms. During a long task the page ignores taps.

6 files are served with short cache lifetimes, so returning visitors download them again (52 KiB).

17 KiB could be saved by minifying JavaScript.

Polyfills for old browsers add 9 KiB JavaScript that modern phones do not need.

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

The page becomes fully interactive after 17.9 s. Good is under 3.8 s.

Your largest element takes 4.3 s to render on a phone. Google's threshold for “good” is 2.5 s. The largest element is the image “Header Image”.

Scripts block taps and scrolling for 694 ms in total while the page loads. Good is under 200 ms.

Visually, the page fills in at 5.8 s (Speed Index). Good is under 3.4 s.

The first text or image appears after 2.8 s on a phone. Good is under 1.8 s.

3 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 82 ms to 87 ms at the 75th percentile (Chrome UX Report (opens in a new tab) history).

Over the last 25 four-week periods to 2026-10-24, real Chrome visitors' largest content (lcp) went from 1.9 s to 1.8 s at the 75th percentile (Chrome UX Report (opens in a new tab) history).

Your homepage downloads 3.2 MB in 109 requests on a phone: scripts 1.9 MB (41), fonts 494 KiB (9) and other files 418 KiB (9). Under 2 MB keeps phones on slow connections fast.

1 image is downloaded at several times the size a phone draws it, for example straatbeeld-home-1600x287-1-min.jpg at 1,600 px wide, shown at 390 px. Resized copies would save about 36 KiB.

1 image (77 KiB) is JPEG, PNG or GIF. The same pictures as WebP or AVIF are usually much smaller at the same quality, and every current browser shows them.

By the Sustainable Web Design model, a visit to your homepage emits about 0.90 g of CO₂e: 107.5 kg a year at 10,000 visits a month. It scales with page weight, so every byte cut lowers it.

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

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

Elements must only use permitted ARIA attributes: 3 elements on the page fail this check, rated serious by axe-core.

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

12 images have no alt text, which hurts accessibility and image search.

All page content should be contained by landmarks: 6 elements on the page fail this check, rated moderate by axe-core.

30 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.

Your meta description is 161 characters; Google truncates after about 160, so the end of your pitch is cut.

The homepage links to 203 pages on trimbos.nl and 26 external pages.

https://www.trimbos.nl/over-trimbos/websites, https://www.trimbos.nl/kennis/themas, https://www.trimbos.nl/kennisbank, https://www.trimbos.nl/actueel/nieuwsbrieven and https://www.trimbos.nl/over-trimbos/organisatie use the same meta description. A description written for each page earns more clicks.

https://www.trimbos.nl/kennisbank has no <h1> headline, so visitors and search engines get no clear main topic.

https://www.trimbos.nl/kennisbank took over 3 s to send its HTML from our server.

We fetched 15 pages linked from your homepage (of 92 found) and read each the way a search engine does.

7 of 22 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 “acf is not defined”.

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 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 953 words of visible text.

Before a visitor clicks anything, the page loads Google Ads and Google Tag Manager (measured from a US location before any click). A consent tool (Cookiebot) is installed; check it blocks these until visitors agree where the law requires it.

Opening the homepage sets 5 cookies (measured from a US location before any click).

Loading the homepage contacts 14 hosts run by other companies (fonts, scripts, analytics, ads), each of which sees the visitor's IP address.